4-H and Youth Development

Our webpages must be accessible so we have our documents in printable/downloadable PDF version first, then we have the document in a webpage version. You may need to scroll through the page to find the document you are looking for.

Documents on this page:

  1. 4-H Enrollment: Link to enrollment forms and instructions
  2. 4-H Enrollment: Civil Rights form for Leaders
  3. 4-H Member/Leader Forms: Medical Release Form
  4. 4-H Member/Leader Forms: Permission to Travel Form
  5. 4-H Member/Leader Forms: State Code of Conduct Form
  6. 4-H Member/Leader Form: Media Release Form
  7. Market Livestock Project: Small Livestock Scale Use Contract Check Out Form
  8. Market Livestock Project: Sheep Sheer Use Contract & Check Out Form
  9. Misc. Documents: Flathead County Scholarship Form
  10. Misc. Documents: 4-H Fundraiser Form
  11. Misc. Documents: Using the 4-H Name and Emblem
  12. Pasture Management: Pasture Management Tips
  13. Pasture Management: Overgrazing Article
  14. Spiders, Insects and Plant Disease: Grasshopper Insecticide Module
  15. Spiders, Insects and Plant Disease: Grasshopper Management Module
  16. Spiders, Insects and Plant Disease: Grasshopper Scounting Module
  17. Spiders, Insects and Plant Disease: Bark Beetle
  18. Spiders, Insects and Plant Disease: Douglas Fir Tussock Moth
  19. Spiders, Insects and Plant Disease: How to Identify a Hobo Spider
  20. Spiders, Insects and Plant Disease: Managing Mountain Pine Beetle
  21. Spiders, Insects and Plant Disease: Montana Bee Identification Guide
  22. Spiders, Insects and Plant Disease: MSU IPM Biological Controls
  23. Spiders, Insects and Plant Disease: Needle Cast Diseases of Conifers
  24. Spiders, Insects and Plant Disease: Powdery Mildew Coloradow State Extension
  25. Spiders, Insects and Plant Disease: Raspberry Cane Borer New Hampshire
  26. Spiders, Insects and Plant Disease: Spider Identification and Management MSU Montguide
  27. Spiders, Insects and Plant Disease: the use of BT for Spruce Bud Worm
  28. Spiders, Insects and Plant Disease: Western Spruce Bud Worms
  29. Weeds: Blueweed
  30. Weeds: Curly Leaf Pond Weed
  31. Weeds: Eurasian Watermilfoil
  32. Weeds: Flowering Rush
  33. Weeds: Hoary Alyssum
  34. Weeds: Knapweed
  35. Weeds: Reveqitation of Cheat Grass Invested Range Land
  36. Weeds: Scotch Broom
  37. Weeds: The Knotweed Complex
  38. Weeds: Western Salsify
  39. Weeds: White Bryony
  40. Weeds: Whitetop
  41. Weeds: Yellow Starthistle
  42. Weeds: Yellowflag Iris
  43. Weeds: Montana Knapweed
  44. Weeds: Oxeye Daisy
  45. Yard and Garden: Composting Article
  46. Yard and Garden: Frost free Days Chart-MSU Creston research Station
  47. Yard and Garden: Ground Squirrels
  48. Yard and Garden: Home garden Soil Testing MontGuide
  49. Yard and Garden: Proper Watering
  50. Yard and Garden: Spray Schedule for Apple Trees-WSU
  51. Yard and Garden: Spray Schedule for Cherry Trees-WSU
  52. Yard and Garden: Spray Schedule for Peach and Apricot Trees-WSU
  53. Yard and Garden: Spray Schedule for Pear Trees-WSU
  54. Yard and Garden: Spray Schedule for Plum and Prune Trees-WSU

4-H Enrollment

Go to http://flathead.msuextension.org/enrollment.html for enrollment forms and instructions.

Printable version of Civil Rights Form for Leaders (PDF)

October 1st                          

                                Re: Civil Rights Compliancy Notification

Dear Flathead County 4-H Volunteer Leader,

The following policies are in effect for all associated with the Montana State University Extension Service 4-H/Youth Program.   The purpose of this policy statement is to ensure that the Montana 4-H Program is inclusive rather than exclusive.

Montana State University and its constituent colleges and programs, including the Montana State University Extension 4-H/Youth program do not discriminate on the basis of race, color, national origin, sex, sexual preference, marital or parental status, age, religion, creed or political belief, mental or physical handicap or disability, or status as a Vietnam era or disabled veteran in admission, access to, or conduct of its educational programs and activities nor in its employment policies and practices.   Discrimination in the 4-H/Youth programs is contrary to the purposes and policies of the Extension Service, Montana State University, the State of Montana, and the United States Department of Agriculture and is prohibited.

Participation in Montana 4-H and its programs is open to all interested youth regardless of race, color, national origin, sex, sexual preference, religion, creed, political belief, marital or parental status or disability. Participation in some programs or aspects of 4-H may be subject to certain age requirements, specific enrollment deadlines, or specific ownership deadlines. A participant, applicant for participation, professional or volunteer staff member, or any person needing accommodation because of a disability should request accommodation form the County Extension Agent.   

Montana State University afford any participant, applicant for participation, or professional or volunteer staff member who believes he or she was discriminated against by the Extension 4-H/Youth program has the right to file a grievance on grounds of discrimination. Complaints of discrimination should be reported to the Human Resources/Affirmative Action Office, Box 172430, MSU-Bozeman, Bozeman, MT 59717-2430. TDD (text telephone): (406) 994-4191 Phone (406) 994-2042.

Please be aware of these policies. For our records, sign the certification statement at the bottom of this letter and return it to the Extension Office. 


Flathead County Extension Agent

This is to certify that ____________________________________________

                                                                Printed Name of Volunteer

will not exclude any person from membership or participation because of race, color, creed, age, national origin, religion, sex, or handicap.

 ____________________________________               _______________

Signature                                                                                               Date

4-H Member/Leader Forms

Printable vForm (PDF)ersion of Medical Release 

Medical Release Form for 4‐H Youth & Adults


Name: ____________________________________________County: _______________________________________

Address: ________________________________________________________________________________________

Name of Parent or Legal Guardian: (YOUTH ONLY): ______________________________________________________

Primary Physician: _____________________________________________ Phone: ____________________________

Dentist: ______________________________________________________ Phone: ____________________________


Primary Contact: _______________________________________ Phone: ___________________________________

Relationship: _________________________City: ___________________________________ State: ______________

Alternate Contact: _______________________________________ Phone: __________________________________

Relationship: _________________________City: ___________________________________ State: ______________


Name of Insurance Carrier: ________________________________________________________________________

Policy Holder Name: ____________________________________ Policy #: __________________________________

Date of Last:

Tetanus Shot: _________ Polio Shot: _________ Mumps Shot: _________ Measles Shot: _________Rubella Shot: __________

Medical Information: (check all that apply and explain if necessary)

□ Stomach or Intestinal problems

□ Diabetes or hypoglycemia (low blood sugar)

□ Nervous disorder (convulsions, epilepsy, dizziness, ect)

□ Respiratory problems

□ Heart Disease

□ Any allergies to medication

□ Any allergies to food or plants

□ Special diet or food restrictions

□ Are you currently under a doctor's care?

□ Are you currently taking medications?

□ Are there any physical restrictions or medical problems

that may require special considerations?





I, _______________________________________ do herby give permission to ______________________________________

to seek and obtain any medical care necessary for my child _____________________________________________________ .

Parent/Guardian Signature _________________________________________________ Date __________________________


To the Best of my knowledge, accurate information has been provided in all areas of this form.

Participant Signature (youth/ adult) ___________________________________________ Date _________________

IF YOUTH: Parent/Guardian Signature __________________________________________ Date _________________

The Montana State University Extension Service is an ADA/EO/AA/Veteran's Preference Employer and Provider of Educational Outreach.


YOUTH Participant Name

Printable version of Permission to Travel Form (PDF)


Date: ____________

County:  Flathead                            

Name of Participant: _____________________________________

MSU Extension 4H programs schedule a number of activities and events which involve travel by way of motor vehicle. When part of the activity or event, the authorized organizers of these activities and events may coordinate, arrange, and/or provide transportation for 4H participants.

All participants are expected to utilize this transportation, as it is provided, unless written permission from the 4H participant's parent(s) or legal guardian is obtained by use of this form.

MSU Extension 4H recognizes that there are circumstances wherein the 4H participant may be required or chooses to provide his/her own transportation in conjunction with scheduled 4H activities or events. MSU Extension 4H may allow 4H participants to opt out of the transportation provided by the authorized 4H event organizers. In order to opt out of the travel requirements set forth by the authorized 4H activity or event organizers, the participant and parent/legal guardian must authorize and request this alternative to 4H provided transportation by completion of the following:

As a Participant:

I hereby request to be allowed to provide for my own travel to any or all events or activities scheduled by a 4-H club or MSU Extension 4-H. This includes operating my own vehicle, a vehicle provided by       another, or traveling with an individual of my choice. By doing so, I understand the risks associated with this travel option and hereby agree to hold harmless, Montana State University, MSU Extension 4H, the State of Montana, 4H leaders, volunteers, officials, sponsors, supervisors or other MSU Extension 4H authorized individuals for any personal injury or claim resulting from my travel to or from any 4H activity or event.

Participant's Signature___________________________________________ Date_____________ 

As Parent or Legal Guardian:  

I hereby request and authorize my minor child to travel to any or all MSU Extension 4H activities or events organized, scheduled, or arranged by a 4-H club or MSU Extension 4-H by traveling with the person of my child's choice or by operating his/her own motor vehicle or a motor vehicle provided by another. In requesting and authorizing travel not arranged or provided by the authorized 4H activity or event organizers or officials, I clearly understand the risks associated with my child's travel and assume all risks thereof. I hereby agree to hold harmless, defend and indemnify Montana State University, MSU Extension 4H, the State of Montana, 4H leaders, volunteers, officials, sponsors, supervisors or other MSU Extension 4H authorized individuals for any personal injury or claim resulting from my child's travel to or from any 4H activity or event. 

Parent/Legal Guardian Signature __________________________________ Date_____________

Both participant and parent/legal guardian must sign

The Montana State University Extension Service is an ADA/EO/AA/Veteran’s Preference Employer and Provider of Educational Outreach.

Printable version of State Code of Conduct Form (PDF)


The 4-H Center & Montana State University Extension wants your participation in 4-H events and activities to be filled with exciting experiences, new friendships and fun. To ensure a positive experience for all participants, it is expected that each participant be considerate of others, participate fully in the programming and observe the following expectations (if a situation or question arises which is not clearly covered by this list, ask a chaperone or staff person before acting).


  • I will conduct myself at all times in order to be a credit to the club, school and community. • I will dress neatly and appropriately for the occasion. • I will show respect for the rights of others to be courteous at all times. • I will be honest and not take unfair advantage of others. • I will respect the property of others. • I will refrain from loud boisterous talk, swearing and horseplay. • I not use my personal vehicle when it is not allowed by an event or trip. • I will demonstrate sportsmanship in the contests and meeting, modesty in winning and generosity in defeat. • I will attend sessions promptly and respect the opinion of others in discussion. • I will not purchase or have in my possession any kind of alcoholic beverage, drugs or tobacco. • I will care for the motel/hotel property and respect the rights of other guests of the motel/ hotel/ dorm and observe all rules instituted by the property. • I will be in my room and stay there after curfew time and I will be dressed and out of my room each day by the set time given by the chaperon(s). • I will be prepared to report to my club and other clubs knowledge gained by attending these activities. • I will respect supervision at all times, being responsible to all adults connected with the trip or event.

I have read the above Code of Conduct and understand that my infraction of any of the above rules will be cause for my participation in the trip or event to be terminated and for me to be sent home at my own expense.

Signature of 4-H Member ___________________________________ Date_________________

Parent/Guardian Signature __________________________________ Date_________________

County Agent Signature ____________________________________ Date_________________

Name County

Printable version of Media Release form (PDF)

Media Release Form

Montana State University Extension

Name of participant


Name of event or activity 

Date and Location of event or activity

The MSU Extension Service—4-H may like to use photos or video of your child that was taken during the above event or activity to use in a press release and other publicity related to this event. The photo or film may be used for the following purposes: 

  • Website
  • Press Release
  • News Story
  • Marketing materials
  • Other

Do you authorize the use of photos or video of your child at this event or activity?

YES                     NO 

I consent and agree, individually and, as a parent or guardian of the minor named above, to the foregoing terms and provisions. By signing below, I hereby waive any right that I (and a minor) may have to inspect or approve the copy and/or finished product or products that may be used in connection therewith or the use to which it may be applied. I warrant that I am of full legal age and have every right to contract for the minor in the above regard. I

have also read and understand the conditions of use listed below.

Parent or Guardian Signature                                                                                                       Date                        


  1. We will not use personal details or full names (first name and last name) of any child in a photograph on our web site.
  2. We will not include personal e-mail or postal addresses, telephone or fax numbers on our web site or in other printed publications.
  3. We may use the name of the child in accompanying text or a photo caption.
  4. We may use group or photographs with very general labels.
  5. We will only use images of children in suitable dress, to reduce the risk of inappropriate use of images.

The Montana State University Extension Service is an ADA/EO/AA/Veteran's Preference Employer and Provider of Educational Outreach.

Market Livestock Project

Printable version of Small Livestock Scale Use Contract Check Out Form (PDF)

USE CONTRACT FOR Flathead County 4-H Council Small Livestock Scale

Notice – By signing this document you may be waiving certain legal rights, including the right to sue.

Release and Waiver of Claims; Assumption of the Risk; Indemnification Agreement

In consideration of being allowed to use the equipment provided by Flathead 4-H Council, the Participant, and the Participant’s parent(s) or legal guardian(s) if the Participant is a minor, do hereby agree to the fullest extent permitted by law, as follows:

1) TO ASSUME ALL RISKS associated with the handling of animals and the use equipment in weighing small livestock, even those risks caused by faulty equipment or lack of training administered to the user. The Participant and his/her parent(s) or legal guardian(s) understand that there are inherent risks associated with animal handling and shearing equipment, which may be both foreseen and unforeseen and include serious physical injury and death to the lamb and serious injury to the equipment user.

2) TO RELEASE the owner, affiliates, operators, and agents from all liability for any loss, damage, injury, death, or expense that the Participant (or his/her next of kin) may suffer, arising out of his/her use of the Equipment. The Participant and his/her parent(s) or legal guardian(s) specifically understand that they are releasing any and all claims that arise or may arise from any negligent acts or conduct of the owners, affiliates, operators, and agents to the fullest extent permitted by law. However, nothing in this Agreement shall be construed as a release for conduct that is found to constitute gross negligence or intentional conduct; and

3) TO BE HELD LIABLE in the case of any damage caused to the Equipment during travel, use, storage, etc, the Participant and his/her parent(s) or legal guardian(s) understand that they are responsible for monetary compensation for either the replacement or repair of the Equipment. The Participant is also under the understanding that they are responsible to report any problems associated with the Equipment that occurred under their care and that they are thus responsible for any damages found between the point of equipment check out and the inspection upon the return of said equipment.  

Personal Responsibility

The Flathead 4-H Small Livestock Scale may not be moved from its location.

Non-4-H users agree to pay a $35 use fee to the Flathead 4-H Council.

Users agree to thorough cleaning and disinfecting of the equipment by removing all animal waste from the equipment and its immediate surrounding. Users will also agree to use a disinfectant solution on the equipment.  

The Participant and his/her parent(s) or legal guardian(s) certify that Participant has no physical or mental condition that precludes him/her from using the equipment and that he/she is not participating against medical advice.

The Participant and his/her parent(s) or legal guardian(s) understand that Participant’s use of equipment is voluntary and further understand that they have the opportunity to inspect the Equipment before use.

The Participant and his/her parent(s) or legal guardian(s) understand that Participant is obligated to follow the rules and instructions of the Equipment and that he/she can minimize his/her risk of injury and injury to their animal by doing so and through the exercise of common sense and by being aware of his/her surroundings.

The Participant and his/her parent(s) or legal guardian (s) understand that the knowledge of proper use and handling of the equipment is the full responsibility of themselves and the owner is at no obligation to be held liable for harm or damage to either the Equipment or the participant/animal from misuse or lack of knowledgeable handling.    

If, while using the Equipment, the Participant or his/her parent(s) or legal guardian(s) observe any unusual hazard or malfunction, which they believe jeopardizes the user’s personal safety or that of others/animals, the user and/or his/her parent(s) or legal guardian(s) will remove the animal from the equipment and stop the use of all equipment and shall also bring said hazard or malfunction to the attention of the owner.

To the extent that any portion of this Agreement is deemed to be invalid under the law of the applicable jurisdiction, the remaining portions of the Agreement shall remain binding and available for use by the owner in any proceeding. I HAVE READ AND UNDERSTAND THIS AGREEMENT AND I AM AWARE THAT BY SIGNING THIS AGREEMENT I MAY BE WAIVING CERTAIN LEGAL RIGHTS, INCLUDING THE RIGHT TO SUE.

By signing below, I agree to accept liability for the equipment listed below. I understand that should any damages occur while the equipment is in my possession, I will be held fully responsible and liable for the

Signature       ______________________________________    Date ________________

Contact Name ______________________________________________________

Event & Date _______________________________________________________

Contact Number _____________________________________________________

Printable version of Sheep Sheer Use Contract & Check Out Form (PDF)


Notice – By signing this document you may be waiving certain legal rights, including the right to sue.

Release and Waiver of Claims; Assumption of the Risk; Indemnification Agreement

In consideration of being allowed to use the equipment provided by Flathead 4-H Extension and Flathead Sheep Committee, the Participant, and the Participant’s parent(s) or legal guardian(s) if the Participant is a minor, do hereby agree to the fullest extent permitted by law, as follows:

1) TO ASSUME ALL RISKS associated with the handling of animals and the use equipment in shearing lambs, even those risks caused by faulty equipment or lack of training administered to the user. The Participant and his/her parent(s) or legal guardian(s) understand that there are inherent risks associated with animal handling and shearing equipment, which may be both foreseen and unforeseen and include serious physical injury and death to the lamb and serious injury to the equipment user.

2) TO RELEASE the owner, affiliates, operators, and agents from all liability for any loss, damage, injury, death, or expense that the Participant (or his/her next of kin) may suffer, arising out of his/her use of the Equipment. The Participant and his/her parent(s) or legal guardian(s) specifically understand that they are releasing any and all claims that arise or may arise from any negligent acts or conduct of the owners, affiliates, operators, and agents to the fullest extent permitted by law. However, nothing in this Agreement shall be construed as a release for conduct that is found to constitute gross negligence or intentional conduct; and

3) TO BE HELD LIABLE in the case of any damage caused to the Equipment during travel, use, storage, etc, the Participant and his/her parent(s) or legal guardian(s) understand that they are responsible for monetary compensation for either the replacement or repair of the Equipment. The Participant is also under the understanding that they are responsible to report any problems associated with the Equipment that occurred under their care and that they are thus responsible for any damages found between the point of equipment check out and the inspection upon the return of said equipment.  

Personal Responsibility

The Participant and his/her parent(s) or legal guardian(s) certify that Participant has no physical or mental condition that precludes him/her from using the equipment and that he/she is not participating against medical advice.

The Participant and his/her parent(s) or legal guardian(s) understand that Participant’s use of equipment is voluntary and further understand that they have the opportunity to inspect the Equipment before use.

The Participant and his/her parent(s) or legal guardian(s) understand that Participant is obligated to follow the rules and instructions of the Equipment and that he/she can minimize his/her risk of injury and injury to their animal by doing so and through the exercise of common sense and by being aware of his/her surroundings.

The Participant and his/her parent(s) or legal guardian (s) understand that the knowledge of proper use and handling of the equipment is the full responsibility of themselves and the owner is at no obligation to be held liable for harm or damage to either the Equipment or the participant/animal from misuse or lack of knowledgeable handling.    

If, while using the Equipment, the Participant or his/her parent(s) or legal guardian(s) observe any unusual hazard or malfunction, which they believe jeopardizes the user’s personal safety or that of others/animals, the user and/or his/her parent(s) or legal guardian(s) will remove the animal from the equipment and stop the use of all equipment and shall also bring said hazard or malfunction to the attention of the owner.

To the extent that any portion of this Agreement is deemed to be invalid under the law of the applicable jurisdiction, the remaining portions of the Agreement shall remain binding and available for use by the owner in any proceeding. I HAVE READ AND UNDERSTAND THIS AGREEMENT AND I AM AWARE THAT BY SIGNING THIS AGREEMENT I MAY BE WAIVING CERTAIN LEGAL RIGHTS, INCLUDING THE RIGHT TO SUE.

The U.S. Department of Agriculture (USDA), Montana State University and the Montana State University Extension prohibit discrimination in all of their programs and activities on the basis of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital and family status. Issued in furtherance of cooperative extension work in agriculture and home economics, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Jeff Bader, Director of Extension, Montana State University, Bozeman, MT 59717

By signing below, I agree to accept liability for the equipment listed below. I understand that should any damages occur while the equipment is in my possession, I will be held fully responsible and liable for the full amount of the repairs/replacement of the equipment.

Date Out





Date In





























































































































































Misc. Documents

Printable version of Flathead County Scholarhship Form (PDF)

Flathead County 4-H Scholarship Form

Name: _____________________________ Age: _________ Years in 4-H: __________

Address: ______________________________________________________________

Phone: ____________Club: _______________________________________________

4-H Projects: ___________________________________________________________

Name and Date of Clinic/Seminar/Event:____________________________________________________


Cost of Clinic/Seminar/Event: _____________________________________________


Estimated Travel Expenses: _______________________________________________

Please answer the following questions-

How would this clinic/seminar/event better our 4-H projects?


How will you utilize this information to help your projects or club?


What are two goals you would like to attain by attending this clinic/seminar/event?





It is appreciated that if you are gifted funds, you will need to provide a thank you and have an active role in giving back to the 4-H community in volunteering with another clinic, your club, or any fundraising event that is put on.

Please return for or direct questions to the Extension Office.

Printable version of 4-H Fundraiser Form (PDF)

Request must be submitted to Extension Office two weeks prior to fundraising activities


Date Received


Date Approved


Person(s) making request:                                                                                                                                         Phone: Event Start Date:                                                                             Event End Date:

Name of Activity/Event: 

Description (include educational purpose, who will benefit from this 4-H event, activity, or fundraising):



What will funds/awards be used for:

Destination of event proceeds:

Club Account



4-H Council





Permission and Release Forms will be needed for any non 4-H participants. (EX Open horse show Permission/Release Form must be signed for non 4-H participants.) Permission/Release Forms are available at the Extension Office.   Person responsible must have form prior to event and it must be attached to this form after the event.

Completed form must be returned 2 weeks after completion of 4-H event/activity/fundraiser event.

Due Date:

  • National/State Policy: All fundraising or use of the 4-H emblem may only be used with approval and is restricted to being used for 4-H educational events or activities.   No use of funds can be utilized for a private individual or cause. This approval allows the event or activity to use the 4-H name and emblem. Any trophies or ribbons must contain the 4-H emblem.   For additional information, see State 4-H Treasure Handbook. 

Expenses: (supplies, rentals, meals, equipment, insurance, mileage—itemize all costs and include copies of all receipts) attach additional pages if needed.

Amount ($) Item Description



Total ($):

Income: (Itemize registration fees, entry fees, donations—Include copies of deposit slips or receipts) Amount ($)             Item Description



Total ($):

List all 4-H members, leaders and or parents that have or will participate or benefit from this event/activity/ or fundraiser: (attach additional pages if necessary.)



Signature of MSU Extension Agent Approving                     Signature of Requestor

Return form to:

MSU/Flathead County Extension

1108 South Main St., Kalispell

MT 59901 or by email to


The programs of the MSU Extension Service are available to all people regardless of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or family status. Issued in furtherance of cooperative extension work in agriculture and home economics, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Jeff Bader, Extension Service Director, Montana State University, Bozeman, MT 59717.

Printable version of Using the 4-H Name and Emblem (PDF)

Using the 4-H Name and Emblem

4-H National Headquarters Fact Sheet

The 4-H Youth Development Program is the youth outreach program from the Land Grant Universities, Cooperative Extension Services, and the United States Department of Agriculture. The 4-H Name & Emblem is intended to represent the ideals of the program with its focus on Head, Heart, Hands, and Health. Today, it is one of the best-known and most valued images emblematic of a century of 4-H achievement. The 4-H Name & Emblem is very important to us as an organization because it represents who we are.

What is the 4-H Name & Emblem?

The official 4-H Emblem is a clover with four leaves and an “H” on each leaf. The clover’s stem must point to the right as you look at the image. The 4-H Emblem is not a plain four-leaf clover. The 4-H Emblem should appear in specific colors and in its entirety. The 4-H Name & Emblem belongs to the 4-H Youth Development Program, under the authority of USDA and anyone wishing to use it must obtain permission to use it ahead of time.

How Do I Get Permission to Use the 4-H Name and Emblem?

It depends on who you are and for what reason you wish to use the 4-H Name & Emblem: 4-H Club or Program member or volunteer leader? Commercial vendor? Event, activity or program affiliated with 4-H? Private, non-profit organization?

If you are a 4-H member or volunteer, you are permitted to use the 4-H Name & Emblem once your program is chartered with the official 4-H Charter from 4-H National Headquarters at the Institute of Food and Agriculture (NIFA ), within the United States Department of Agriculture (USDA). If you are a commercial vendor, private organization or any other entity, you need to contact either the local Cooperative Extension Service office or the State 4-H Office to determine what steps you need to take for your use of the 4-H Name & Emblem. Anyone wishing to use the 4-H Name & Emblem in a way that does not specify a local or state program, should seek authorization to use the 4-H Name & Emblem from 4-H National Headquarters at USDA.

In all private and commercial use of the 4-H Emblem, the statement “18 USC 707” must legibly appear either to the right of the base of the stem or below the lower right leaf of the clover. In use internal to the Cooperative Extension System (all 4-H Youth Development programs and clubs duly given authorization to use the 4-H Name & Emblem) use of the statement is at the discretion of the State 4-H Program Leader, or for those uses that are multi-state, regional, or national in scope, at the discretion of 4-H National Headquarters.

Whoever uses such emblem or any sign, insignia, or symbol in colorable imitation thereof, or the words “4-H Club” or “4-H Clubs” or any combination of these or other words or characters in colorable imitation thereof, without being duly authorized, shall be fined not more than $5,000 for individuals and $10,000 for groups, or imprisoned not more than six months, or both.

Did You Know? The 4-H Name & Emblem is a highly valued mark within our country’s history. As such, it was granted a very unique and special status; it is in a category similar to the Presidential Seal and the Olympic Emblem. This federal protection makes it a mark into and of itself with protection that supercedes the limited authorities of both a trademark and a copyright. As a result, responsibility and stewardship for the 4-H Name & Emblem were not given to the U.S. Patent Office but were given to a higher level of the federal government, a member of the Cabinet, the Secretary of Agriculture. The Secretary has responsibility for the 4-H Name and Emblem, at the direct request of Congress. The “18 USC 707” is the statement in the United States Code that outlines the protection of the 4-H Name & Emblem.

4-H National Headquarters; 1400 Independence Avenue, S.W.; MS 2225;

Washington, D.C. 20250


Using the 4-H Name & Emblem: Graphics Basics

The Official 4-H Emblem

The Official 4-H Emblem is a 4-leaf clover with an H in each leaf, with the stem turned to the right. The Emblem may be two-dimensional (flat) or three dimensional (with shadows that show depth and perspective). Authorized users of the 4-H Emblem should take care to ensure that when they use the Emblem, they have done the following:

  1. They have obtained the Official 4-H Emblem and are using it in its entirety.
  2. They do not “flip” the image to create a framed look. The stem on the 4-H Emblem must point to the right as you look at the image. Under no circumstances should the stem be changed to point to the left.
  3. They are familiar with resizing graphics through the software application being used, and do not distort or warp the dimensions of the Emblem.
  4. The 4-H Emblem is never used to imply endorsement of any product or material.
  5. They follow the graphic use guidelines outlined in this document, or for additional informa-tion, contact 4-H National Headquarters.

Use the Whole Emblem

The 4-H Emblem should always appear in its entirety - meaning it should always appear as a whole and complete image - the image recognized by millions of people. This means:

don’t remove any leaves. If you are using a clover image that has an “H” on each leaf, the leaves cannot be removed or have another image superimposed over the top of one of the leaves. Other images should be moved and appear completely separate from the 4-H Emblem. This also means you shouldn’t “cut off” a leaf by running it off the edge of the paper in print media or other designs.

Don’t place text or other images over or on top of the 4-H Emblem. The 4-H Emblem should not appear screened under words or graphics. No photo, drawing, symbol, word or other figure or object may be placed on or obscure the 4-H Emblem. This includes on web pages, where it should not appear as a “watermark” behind other information.

Keep it Upright

In general, the 4-H Emblem should not be rotated or turned on its side. There are some excep-tions, such as on fabric where the emblem is scattered randomly across the fabric or in other random designs. If you are considering an exception, please contact the 4-H National Head-quarters.


The 4-H Emblem should never be screened, shaded, gradated, or appear in a multi-colored hue. The official and pre-ferred color of the 4-H Emblem is 100 percent PMS 347 green, (The H’s reversed out to the color of the paper on which the emblem is printed). The clover can also be white, black, or metallic gold. The H’s on the clover can be white, metallic gold (only on a green clover), green (only on a white clover), or black. The clover can be outlined in green (for white clo-ver) or white (for green clover) to add prominence to the image and make the emblem stand out from the background.

One-color printing requires either PMS 347 green or black. For commercial applications, the “18 USC 707” notice should be the same color as the clover leaves. Black is the only acceptable alternative to green for one-color printing and should be used only when cost prohibits green ink or color photocopies.

Two-color printing—Only PMS 347 green may be used for the leaves and “18 USC 707” notice—the H’s will be re-versed out of the PMS 347 to be white or the color of the paper on which the emblem is printed. The H’s may also be printed in metallic gold (PMS 873) on a green background.

Four-color process (full color printing)—In four-color process printing, PMS colors are approximated using a particular combination of the standard four-color process printing inks. The four-color process percentages required to match 4-H’s PMS 347 green are: cyan 100%, magenta 0%, yellow 90%, and black 0%. There is no CMYK equivalent to PMS 873.

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, and marital or family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W , Whitten Building. 14th and Independence Avenue, SW, Washington, DC 20250-9410 or call (202) 720-5964 (voice or TDD). USDA is an equal opportunity provider and employer.

Video and Computer Screen Colors (Electronic Media) The colors transmitted by electronic media are created using precise combinations of RGB (red, green, blue). The correct RGB values for the 4-H green are: R=51, G=153, B=102. No other colors are acceptable.

For exceptions to the guidance provided regarding color, especially in non-print or corollary materials, please contact 4-H National Headquarters.

Distortion and Proportion

The appearance, shape, and proportion of the 4-H Emblem should never be distorted to fit in an imprint space. Do not make the 4-H Emblem longer, taller, wider or angled. Do not alter the shape in any way. The overall size of the 4-H Em-blem may be changed, but the proportions must remain intact. All standard word processing software applications allow you to scale an image while maintaining its original proportions. Before rescaling the 4-H Emblem, please consult your software manual for proper instructions. Do not make the 4-H Emblem so small that the H’s are no longer clearly legible.

Using the 4-H Name

The official 4-H Name includes 4-H, 4-H Youth Development, or 4-H Youth Development Program. When using the term “4-H” it must conform as follows:

Numeral “4” separated from a capital “H” with a hyphen (not a dash, slash or space).

It is well documented in English usage, as well as in the most familiar style manuals, that you should never begin a sentence with a numeral. To comply with this rule, you would need to begin a sentence using “Four-H.” This language rule, however, is contrary to the regulations set down for use of the 4-H Name & Emblem; if such a situation arises in writings, it is far better to re-word the sentence slightly to avoid the language rule. An exception to this would be in writing news headlines where the 4-H name would be better served by using the familiar numeral-hyphen-letter com-bination to provide instant recognition.

Do not use the 4-H Emblem in place of the word “4-H” in a title or text.

Avoid separation of any of the elements of the 4-H Name at the end of sentences. This can sometimes be difficult be-cause some software programs override user commands. Often, these overrides do not become visible until after printing or posting to a web page: careful scrutiny of text after trial printing or posting is advised. If such overrides occur, try rewording your sentence to keep the entire name on the same line or add a small word or space between words to force the separated portions together on the next line.

Using the 4-H Emblem on Collateral Items

The 4-H Emblem can be used for collateral materials such as jewelry or fine art and may be made of metal (e.g. copper, bronze, gold or silver), glass, leather, or wood without conflicting with the color specifications for the 4-H Emblem. Ce-ramic, plaster, paper, fabric or any materials that are colored or painted must comply with the color specifications and all other guidelines.

Use of the emblem on fabric, whether painted, screen printed, embroidered, appliquéd, or some other technique, must accurately represent the 4-H Emblem in authorized colors and adhere to all other use guidelines.

The 4-H Emblem is not open to reinterpretation or reconfiguration, regardless of its intended use, including the develop-ment of materials such as jewelry, sculpture, furniture, signage, crafts, or other fine art.

Using the 4-H Name and Emblem in Animation

Animation of the 4-H Name & Emblem is allowable provided that the animation is in keeping with the guidelines, and that at the end point of the animation (where the animated loop begins to repeat, if in an ongoing loop), the 4-H Name & Em-blem appear in a manner that meets all guidelines for its use. Effects that may be used as part of an animation loop in-clude: swivel and rotate, transition and dissolve, fly-by, layer, and posterization.

Animation may also show the 4-H Emblem on a waving flag, on a float that is partially hidden by crowds watching a pa-rade, being placed in a box or behind a curtain, twirling as it “dances,” “separating” as it forms the doors opening to welcome you to the 4-H Program, be partially hidden as it forms the backdrop for a youth speaking about 4-H, slowly come into focus or formation as the 4-H Emblem from an amorphous or other background, or completing itself as the clo-ver leaves are added one by one to form the 4-H Emblem and each “H” is explained. In each of these cases, the 4-H Em-blem may be temporarily blocked, in whole or in part, or have its shape altered. The end point of the animation must still comply with the guidelines.

For additional information or guidance related to animation applications for the 4-H Name & Emblem, contact 4-H Na-tional Headquarters.

Using the 4-H Name and Emblem in Partnership with Others

The 4-H Name & Emblem may be used in conjunction with the names, emblems, and word marks of other organizations and programs when 4-H is a partner, co-author, sponsor, or supporter or in some other official relationship. When feasi-ble, the nature of the relationship among the organizations or programs should be clearly defined (e.g., in partnership with, sponsored by, etc.), and the 4-H Emblem should be given prominence consistent with its role in the relationship.

The 4-H Emblem should not be used or integrated into a larger design in such a manner that it becomes difficult to recog-nize or distinguish, or that is not consistent with the graphic guidelines for use of the 4-H Emblem.

To avoid the appearance of endorsement of a program, product, or service, the 4-H Emblem may not be incorporated into a larger design of a program, product, or service that is protected by trademark, service mark, copyright, or other similar laws. It is not acceptable to incorporate the 4-H Emblem into any other organization’s logo or emblem. The author-ity for determining the proper display and use of the 4-H Emblem rests with 4-H National Headquarters.

Permission to use the 4-H Name & Emblem is not required when the 4-H Name & Emblem is used to link to an official 4-H

website in keeping with the policies and guidelines of 4-H National Headquarters.

Downloadable Graphics

The official 4-H Emblem and versions for print and the web are available for download at:


Each of the download files contains both black and white, and two-color and three-color versions of the 4-H Emblem in EPS, TIFF and GIF formats, for Mac and PC. The EPS files are especially suited for “Postscript” printers and Mac-based units. In general, TIFF files may be used with any printer type. Test both formats with your software and printer to find which yields the best results.

Making 4-H Name and Emblem Decisions

This document is meant to be a quick reference for using the 4-H Name & Emblem. The 4-H National Headquarters at NIFA, USDA provides further documentation on the official headquarters web site:


If your questions are not answered here, please go to the URL above and click on the 4-H Name & Emblem link. Carefully

researching the 4-H Name & Emblem section of the 4-H National Headquarters website should answer your questions. If you need more information or clarification contact National 4-H Headquarters for help at 4HNE@nifa.usda.gov.

Portions of the content and graphics used in this document were taken from “4-H Emblem Use and Graphic Standards,”

http://4h.ifas.ufl.edu/newsandinfo/ClipArt/4hemblem.htm, Ami Nieberger-Miller, University of Florida, Gainesville, FL. Special thanks: Laura Stone and Dallas Woodrum, N4-HYTLT, for publication design, and to the 4-H Name & Emblem Working Group.

The 4-H Name & Emblem is protected under “18 USC 707.”

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, and marital or family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W , Whitten Building. 14th and Independence Avenue, SW, Washington, DC 20250-9410 or call (202) 720-5964 (voice or TDD). USDA is an equal opportunity provider and employer.


Pasture Management

Printable version of Pasture Management Tips (PDF)

Pasture Management Tips

Small parcels of land less than 100 acres continue to be a land management challenge. Often people that move into the valley have never cared for more than a residential lot. They tell me that they have moved to the Flathead to “live the Montana Dream.” Often this means, to them, owning horses and/or cattle. What I’d like to address is that there is a discrepancy between what is allowed by law and what are good land stewardship practices.

Flathead County zoning department states that certain residential areas are approved to have two horses per acre. Real estate agents use this to sell property. “sure you can put 10 horses on this five-acre piece of ground. Why not?” When the five acre ranchette becomes a dry lot filled with weeds, the resident doesn’t always know what happened. Montana State University range specialist, Jeff Mosely, said that with the rainfall in the Flathead, the stocking rate should be one animal unit per 10 acres. An animal unit is a 1,000 lb. cow-calf pair. A horse is considered 1.5 animal units. A horse rarely stops grazing while cows lay down to ruminate several times a day. Stocking rates can be adapted depending on a land owner’s willingness to use alternative methods such as using a dry lot, rotational grazing, irrigation and assorted grass varieties.

Understanding the physiology of grass and the impact of over grazing is critical to good management. Grasses do not store all of their carbohydrates (energy) in their roots like other plants. The grass stores most of its carbohydrates in the lower 2-3” of the blade. Livestock prefer eating this lower portion because it is sweeter to the taste and more palatable. Once this area of the plant is removed, there is no energy to regrow the plant. Additionally, roots grow in proportion to the top growth. Grass that has been eaten to about ¼”, have about ½” roots. Grasses that have been allowed to grow to 8-10” have about 12” roots. It’s easy to visualize how over grazed grass is easily pulled from the ground when the roots are barely holding on. Scalped grass also succumbs to drought quickly. Open areas of soil that occur when grass dies or is pulled out, is fertile ground for weed seeds to blow in and become established. Another trait often unrecognized is that our traditional cool season pasture grasses lose their roots after the solstice of June 21 each year. Farmers often call it the “summer slump”. The grass just doesn’t grow. This is due to their preference for cool weather and that they don’t have an active root system. This is the time that the grass needs to rest and recover and not be under pressure by livestock.

Livestock do not eat most of Montana’s noxious weeds. Some are actually poisonous to livestock. When these weeds find an over grazed pasture it is a perfect setting to flourish since the competition for water and nutrients has been eliminated. Jed Fisher, Flathead County Weeds and Parks, says that a high percentage of their calls come from poorly managed livestock facilities. The weeds contain tannins and other compounds that taste bitter to the animal. When left with no other food source, livestock will eventually eat the noxious weed and can become seriously ill or die.

Pasture grass must be allowed to get to 10” or so in the spring before livestock are put on it. When the ground is soft from winter snow melting and early season rains, it is easily compacted by hooves. The grass can be removed by the roots and the carbohydrate stores eliminated. There is no time for the blades of grass to grow and photosynthesize the carbohydrates necessary for survival. I’ve seen pastures made completely useless in less than 2 years by putting livestock on too early. The fall is an important time to be careful of overgrazing also. As mentioned, if the top growth of the grass is too short, there will not be enough roots to survive the winter and no carbohydrates for spring growth.

There is no time of year that over grazing is acceptable. The use of a dry lot to allow pastures to rest is necessary on most farms of limited acreage. The use of electric fence to keep animals rotating through an area can be helpful.

Dr. Emily Glunk is the MSU forage specialist. She is available via email for questions and is planning to continue collaborating with Flathead Extension Agent Pat McGlynn to provide an annual pasture management workshop in Kalispell.

For questions call Pat McGlynn at 758-5554 or pmcglynn@montana.edu

Printable version of Overgrazing Article (PDF)

Overgrazing a common problem on local small-acreage farms


Daily Inter Lake

Ranchettes are plentiful in the Flathead Valley, but if pastures aren’t managed correctly, weeds can also be plentiful. A group of more than 30 small-acreage

horse and cattle owners gathered near Foy’s Lake last week to learn how to avoid overgrazing their land. The free workshop was offered by the Montana State University Extension Service and will become an annual event. “A problem that is increasing in the Flathead Valley has been the number of people who buy small acreage— five to 20 acres — and put several horses on it, wishing to live the ‘Montana Dream,’” said Pat McGlynn, MSU Extension agent for Flathead County. “These horses quickly eat all of the available plants and this is when the problem begins.” Once the grass has been consumed, noxious weeds move in where the soil has been disturbed. “Landowners may not realize that grasses do not store their carbohydrates, or energy in their roots like other plants,” McGlynn said. The grass stores carbohydrates in the lower two to three inches of the blade. When people allow horses, cattle, goats or sheep to eat the grass below a 3-inch level, all the way to the soil, the grass cannot grow back, McGlynn explained. “It has no energy reserves and the meristem, where the plant begins, has been eliminated,” she said. “Only weeds can grow. The weeds are not palatable to the livestock so they avoid them. This is the perfect storm as far as the noxious weed problem in

our area.” McGlynn said she gets calls about pasture management several times a week. She plans to offer the free workshop each summer during the third

week in July. “It was such a good group,” she said of the workshop participants. “So many people said, ‘I have to tell my neighbor about this.’” According to MSU Range Management Specialist Jeff Mosley, 10 acres for one horse, with a five- to sixmonth grazing season, is the recommended stocking rate for the Flathead Valley. But the matter of how many animals a pasture can sustain depends on the length of the grazing season, whether the property is irrigated or not, and whether the animals alternate between a dry lot and grazing land. Flathead County zoning regulations, however, allow two horses per acre in several zoning districts, including suburban agriculture 5- and 10-acre zones and some residential zones. That ratio puts Flathead pasture land at a greater risk of overgrazing if property owners don’t fully understand pasture management, McGlynn said. As summer days get shorter late in the season, grasses shed their roots and that’s when it’s most important to rest pastures. “People really should have their animals on a dry lot in July to August 1 and then put them back out [to pasture],”

McGlynn said. “But no one wants to feed hay when they can see grass ... as soon as the overgrazed land gets a tiny bit of green, animals will overeat because the new growth is more palatable, so the pasture never gets to rest.” Animal owners also may underestimate how much horses eat in a short amount of time, McGlynn said. “They eat so much when they first get out there; they’re nonstop mowing machines,” she said. “Grazing a couple of hours a day isn’t actually resting the pasture. It’s actually hurting it worse than leaving [horses or cattle] out for three days and then taking them off. They can eat 2 percent of their body weight in the first couple of hours.” An added problem with overgrazing is the potential for horses to get sand colic from inhaling sand into their stomachs when the plant material is gone, McGlynn added. “They will also begin eating poisonous weeds if that is all that is left in the pasture,” she said. “Livestock normally instinctually will avoid poisonous material, but if left in an enclosed area with no other choices, they will consume deadly weeds.” More information about stocking rates and

grazing recommendations is available through the local MSU Extension Service; call 758-5553.

Features editor Lynnette

Hintze may be reached at

758-4421 or by email at lhintze@


Spiders, Insects and Plant Disease

Printable version of Grasshopper Insecticide Module (PDF)


A seed treatment product for protection against damage from, or control of, listed

insects on barley, corn, cotton, cucurbit vegetables, legume vegetables (including

soybean), oilseed crops (black mustard seed, borage seed, crambe seed, field mustard

seed, flax seed, Indian mustard seed, Indian rapeseed seed, Rapeseed seed, and

safflower seed), potatoes, rice (dry-seeded), sorghum, sugarbeets, sunflower and wheat

Active Ingredient:

Thiamethoxam1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47.6%

Other Ingredients: 52.4%

Total: 100.0%

1CAS No. 153719-23-4

Cruiser 5FS contains 5 pounds thiamethoxam per gallon.



See additional precautionary statements and directions

for use in booklet.

EPA Reg. No. 100-941

EPA Est. 100-NE-001MHA Product of India

EPA Est. 46073-TN-003NTM Formulated in the USA

Superscript is the first three letters of batch code

on container.

SCP 941B-L3N 0909 301231

1 gallon

Net Contents


If inhaled • Move person to fresh air.

  • If person is not breathing, call 911 or an ambulance, then give

artificial respiration, preferably by mouth-to-mouth, if possible.

  • Call a poison control center or doctor for further treatment


If swallowed • Call a poison control center or doctor immediately for treatment


  • Have person sip a glass of water if able to swallow.
  • Do not induce vomiting unless told to do so by the poison control

center or doctor.

  • Do not give anything by mouth to an unconscious person.

If on skin or


  • Take off contaminated clothing.
  • Rinse skin immediately with plenty of water for 15-20 minutes.
  • Call a poison control center or doctor for treatment advice.

If in eyes • Hold eye open and rinse slowly and gently with water for 15-20


  • Remove contact lenses, if present, after the first 5 minutes, then

continue rinsing eye.

  • Call a poison control center or doctor for treatment advice.

Have the product container or label with you when calling a poison control center

or doctor, or going for treatment.


For 24-Hour Medical Emergency Assistance (Human or Animal)

or Chemical Emergency Assistance (Spill, Leak, Fire or Accident)




Hazards to Humans and Domestic Animals


Harmful if inhaled, swallowed, or absorbed through the skin. Causes moderate eye

irritation. Avoid breathing vapor or spray mist. Avoid contact with skin, eyes, or clothing.

Wash thoroughly with soap and water after handling, and before eating, drinking,

chewing gum, using tobacco, or using the toilet. Remove contaminated clothing and

wash before reuse.


Personal Protective Equipment (PPE)

Applicators, Other Handlers and Re-entry Workers Must Wear:

  • Long-sleeved shirt and long pants
  • Chemical-resistant gloves made of any waterproof material - Category A (e.g.,

natural rubber ≥ 14 mils)

  • Shoes plus socks

Multiple Task Workers must wear:

( Multiple task workers perform multiple tasks in one day such as mixing, bagging/

filling seed containers, product application, bag sewing, and clean up)

  • Chemical resistant gloves
  • Chemical-resistant coveralls over long sleeved shirt and long pants
  • Shoes plus socks

User Safety Requirements

Follow manufacturer’s instructions for cleaning/maintaining PPE. If no such instructions

exist for washables, use detergent and hot water. Keep and wash PPE separately from

other laundry.

Engineering Control Statements

When handlers use closed systems in a manner that meets the requirements listed in the

Worker Protection Standard (WPS) for agricultural pesticides [40 CFR 170.240(d)(4-6)],

the handler PPE requirements may be reduced or modified as specified in the WPS.

User Safety Recommendations

Users should:

  • Wash thoroughly with soap and water after handling.
  • Wash hands before eating, drinking, chewing gum, using tobacco, or using

the toilet.

  • Remove clothing immediately if pesticide gets inside. Then wash thoroughly

and put on clean clothing.

  • Remove PPE immediately after handling this product. Wash the outside of

gloves before removing. As soon as possible, wash thoroughly and change

into clean clothing.

Environmental Hazards

This product is toxic to wildlife and highly toxic to aquatic invertebrates.

Do not contaminate water when disposing of equipment wash water.



NOTICE: Read the entire Directions for Use and Conditions of Sale and Limitation

of Warranty and Liability before buying or using this product. If the terms are not

acceptable, return the product at once, unopened, and the purchase price will be


The Directions for Use of this product must be followed carefully. It is impossible to

eliminate all risks inherently associated with the use of this product. Crop injury, ineffectiveness

or other unintended consequences may result because of such factors as

manner of use or application, weather or crop conditions, presence of other materials

or other influencing factors in the use of the product, which are beyond the control

of SYNGENTA CROP PROTECTION, Inc. or Seller. To the extent permitted by applicable

law, Buyer and User agree to hold SYNGENTA and Seller harmless for any claims relating

to such factors.

SYNGENTA warrants that this product conforms to the chemical description on the label

and is reasonably fit for the purposes stated in the Directions for Use, subject to the

inherent risks referred to above, when used in accordance with directions under normal

use conditions. To the extent permitted by applicable law: (1) this warranty does not

extend to the use of the product contrary to label instructions, or under conditions


reasonably foreseeable to or beyond the control of Seller or SYNGENTA, and (2) Buyer

and User assume the risk of any such use. TO THE EXTENT PERMITTED BY APPLICABLE





To the extent permitted by applicable law, in no event shall SYNGENTA be liable for

any incidental, consequential or special damages resulting from the use or handling











SYNGENTA and Seller offer this product, and Buyer and User accept it, subject to the

foregoing Conditions of Sale and Limitation of Warranty and Liability, which may not

be modified except by written agreement signed by a duly authorized representative



It is a violation of Federal law to use this product in a manner inconsistent with its


Cruiser 5FS may be applied by closed or open system seed treatment application processes.

DO NOT apply more than 215 gallons of Cruiser 5FS per 8-hour day for seed

treatments utilizing a closed system. DO NOT apply more than 38 gallons of Cruiser 5FS

per 8-hour day for seed treatments utilizing an open system.


Use this product only in accordance with its labeling and with the Worker Protection

Standard, 40 CFR part 170. This Standard contains requirements for the protection

of agricultural workers on farms, forests, nurseries, and greenhouses, and handlers

of agricultural pesticides. It contains requirements for training, decontamination,

notification, and emergency assistance. It also contains specific instructions and

exceptions pertaining to the statements on this label about personal protective

equipment (PPE) and restricted-entry interval. The requirements in this box only

apply to uses of this product that are covered by the Worker Protection Standard.

Do not enter or allow worker entry into treated areas during the restricted-entry

interval (REI) of 12 hours. Exception: If the seed is treated with the product and the

treated seed is soil-injected or soil-incorporated, the Worker Protection Standard,

under certain circumstances, allows workers to enter the treated area if there will

be no contact with anything that has been treated.

PPE required for early entry to treated areas that is permitted under the Worker

Protection Standard and that involves contact with anything that has been treated,

such as plants, soil, or water is:

  • Coveralls
  • Chemical-resistant gloves made of any waterproof material - Category A (e.g.,

natural rubber ≥ 14 mils)

  • Shoes plus socks





Treatment of highly mechanically scarred or damaged seed, or seed known to be of low

vigor and poor quality, except for the purpose of curative control of existing disease

pests, may result in reduced germination and/or reduction of seed and seedling vigor.

Treat a small quantity of seed using equipment similar to that planned for treating the

total seed lot. Conduct germination tests on a small portion of seed before committing

the total seed lot to a selected seed treatment. Due to seed quality, crop or variety

sensitivity, and seed storage conditions beyond the control of Syngenta, no claims are

made to guarantee the germination of carry-over seed or propagating material for all

crop seed.


Cruiser 5FS is a systemic seed treatment insecticide belonging to the neonicotinoid class

of chemistry. Cruiser 5FS controls certain chewing and sucking insects through contact

and ingestion. The plant rapidly takes up the active ingredient in Cruiser 5FS as it starts

to emerge and establish. Cruiser 5FS is a selective seed treatment insecticide, and its

use is compatible with integrated pest management programs. The length of control

of the major insect pests will vary depending on the product use rate, insect pressure,

crop growth and maturity, and soil and environmental conditions. When rate ranges

are given, use the higher rate when insect pressure is expected to be high.


Important: Thoroughly shake the container of Cruiser 5FS prior to use.

Apply Cruiser 5FS as a water-based slurry utilizing standard slurry seed treatment

equipment which provides uniform seed coverage. Uneven or incomplete seed coverage

may not give the desired level of insect or disease control. Thoroughly mix the


amount of Cruiser 5FS into the required amount of water for the slurry

treater and dilution rate to be used. The typical density of Cruiser 5FS is 10.5 pounds

per gallon. Consult the manufacturer of the application equipment you plan to use

for suitability for this application and for instructions on operation and calibration of

the equipment.

  • Use an EPA-approved dye or colorant that imparts an unnatural color to the seed

as stated in 40 CFR 153.155 (c).

  • Allow seed to dry before bagging.
  • Store away from feed and foodstuffs.

Cruiser 5FS has been found to be compatible with some liquid inoculant products.

Cruiser 5FS may be mixed or applied sequentially with approved liquid inoculants.

Consult the maker of the liquid inoculants and a Syngenta Crop Protection representative

for directions before applying Cruiser 5FS with inoculants.


The Federal Seed Act requires that bags containing treated seeds shall be labeled with

the following statements:

  • This seed has been treated with Thiamethoxam insecticide.
  • Do not use for feed, food or oil purposes.
  • User is responsible for ensuring that the seed bag meets all requirements under

the Federal Seed Act.

In addition, the U.S. Environmental Protection Agency requires the following statements

on bags containing seeds treated with Cruiser 5FS (thiamethoxam):

  • Store away from food and feedstuffs.
  • Wear long-sleeved shirt, long pants and chemical-resistant gloves when handling

treated seed.

  • Treated seeds exposed on soil surface may be hazardous to wildlife. Cover or


treated seeds spilled during loading.

  • Dispose of all excess treated seed.
  • Do not contaminate water bodies when disposing of planting equipment wash


  • Dispose of seed packaging in accordance with local requirements.
  • In the event of crop failure or harvest of a crop grown from Cruiser 5FS treated

seed, the field may be replanted immediately to barley, canola, corn, cotton,

cucurbit vegetables, fruiting vegetables, legume vegetables, mint (peppermint

and spearmint), oil seed crops (black mustard seed, borage seed, crambe seed,

field mustard seed, flax seed, Indian mustard seed, Indian rapeseed seed, Rapeseed

seed, and safflower seed), rice, root vegetables, sorghum, strawberry, sunflowers,

tobacco, tuberous and corm vegetables and wheat. For any other crop, the minimum

plant back interval is 120 days from the date the Cruiser 5FS treated seed was

planted. A cover crop other than the crops listed above that is planted for erosion

control or soil improvement may be planted sooner than the 120 day interval;

however, the crop may not be grazed or harvested for food or feed.

  • Do not allow children, pets, or livestock to have access to treated seed.
  • Treated seed must be planted into the soil at a depth greater than 1 inch.
  • Dispose of all excess treated seed. Leftover treated seed may be doublesown

around the headland or buried away from water sources in accordance with

local requirements. Do not contaminate water bodies when disposing of planting

equipment washwaters.

  • With the exception of cotton and soybeans, do not make any soil or foliar application

of products containing thiamethoxam to crops grown from seed treated with

Cruiser (thiamethoxam).

  • Do not use at a rate that will result in more than 0.266 lb. thiamethoxam per acre

(120.66 grams a.i./A) per season.

Sunflower Seed Bags Only:

  • To protect the Preble’s Meadow Jumping Mouse, sunflower seed treated with

Cruiser 5FS may not be planted in Elbert or Weld Counties in Colorado. Treated

sunflower seed must be planted at a minimum depth of one inch.


Resistance Management

Some insect pests are known to develop resistance to products after repeated use.

Because resistance development cannot be predicted, the use of this product should

conform to sound resistance management strategies established for the crop and use

area. Syngenta encourages responsible product stewardship to ensure effective longterm

control of the insects on this label.

If resistance to this product develops in your area, this product, or other products with

a similar mode of action, may not provide adequate control. If poor performance cannot

be attributed to improper application or extreme weather conditions, a resistant

strain of insect may be present. If you experience difficulty with control and resistance

is a reasonable cause, immediately consult your local company representative or agricultural

advisor for the best alternative method of control for your area.

Cruiser 5FS contains a Group 4A insecticide (thiamethoxam, belonging to the neonicotinoid

class of chemistry). Insect biotypes with acquired or inherent resistance to Group

4A insecticides may eventually dominate the insect population if Group 4A insecticides

are used repeatedly as the predominant method of control for targeted species. This

may result in partial or total loss of control of those species by Cruiser 5FS or other

Group 4A insecticides.

In order to maintain susceptibility to this class of chemistry:

n Avoid using Group 4A insecticides exclusively for season long control of insect species

with more than one generation per crop season.

n For insect species with successive or overlapping generations, apply Cruiser 5 FS or

other Group 4A insecticides using a “treatment window” approach. A treatment

window is a period of time as defined by the stage of crop development and/or the

biology of the pests of concern. Within the treatment window, depending on the

length of residual activity, there may either be single or consecutive applications

(seed treatment, soil, foliar, unless otherwise stated) of the Group 4A insecticides. Do

not exceed the maximum Cruiser 5 FS allowed per growing season.

n Following a treatment window of Group 4A insecticides, rotate to a treatment window

of effective products with a different mode of action before making additional

applications of Group 4A insecticides.

n A treatment window rotation, along with other IPM practices for the crop and use

area, is considered an effective strategy for preventing or delaying a pest’s ability to

develop resistance to this class of chemistry.

n If resistance is suspected, do not reapply Cruiser 5FS or any other Group 4A


Other Insect Resistance Management (IRM) practices include:

n Incorporating IPM techniques into your insect control program.

n Monitoring treated insect populations for loss of field efficacy.

n Using tank-mixtures or premixes with insecticides from a different target site of

action group as long as the involved products are all registered for the same crop

outlet and effective rates are applied.

For additional information on Insect Resistance Management:

n Contact your local extension specialist, certified crop advisor and/or product manufacturer

for additional insect resistance management recommendations.

n Visit the Insecticide Resistance Action Committee (IRAC) on the web at:


Use Restrictions

Cruiser 5FS may be applied by closed or open system seed treatment application processes.

DO NOT apply more than 215 gallons of Cruiser 5FS per 8-hour day for seed

treatments utilizing a closed system. DO NOT apply more than 38 gallons of Cruiser 5FS

per 8-hour day for seed treatments utilizing an open system.

Commercial treatment of sorghum seed requires the use of a closed system.


To provide early season protection of seedlings against injury by bird cherry-oat aphids,

English grain aphid, greenbug, Hessian fly, Russian wheat aphid, and wireworm, and

to reduce potential spread of barley yellow dwarf virus due to aphid vectors, apply

Cruiser 5FS at 0.75-1.33 fluid ounces per 100 pounds of seed. At the high rate, Cruiser

5FS will reduce grasshopper damage in barley during the early season. For early season

wireworm protection, apply Cruiser 5FS at 0.19 to 0.25 fluid ounces per 100 pounds

of seed.

Corn (Field, Pop, Seed and Sweet Corn)

NOTE: If corn seed to be treated with Cruiser 5FS has existing infestations of stored

grain pests, fumigate the seed prior to treating with Cruiser 5FS and bagging.

NOTE: When treated according to the following directions for post-planting protection

against listed pests, Cruiser 5FS will also provide protection during post treatment storage

of the seed against damage from the following insects: Indian Meal Moth (Plodia

interpunctella), Lesser Grain Borer (Rhyzoperthadominica), Red Flour Beetle (Tribolium

castaneum), and Rice Weevil (Sitophilus oryza).

Consult your Syngenta Seed Treatment representative for specifics on slurry additives

to use during application of Cruiser 5FS.

Follow planter manufacturer instructions for use of talc, graphite, or other hopper box

additives at planting.

It is highly recommended to use registered seed treatment fungicides such as Apron XL®,

Dynasty® and Maxim® XL as the broad spectrum seed treatment fungicide with Cruiser

5FS applications on corn.

To provide early season protection of seedlings against injury by wireworm, seedcorn

maggot, southern corn leaf beetle, chinch bug, corn flea beetle, grape colaspis, white

grub (including Japanese beetle larvae, European Chafer larvae, true white grub,

annual white grub, May/June beetle larvae), black cutworm, thrips, southern green

stinkbug, seedcorn beetle, sugarcane beetle, and corn leaf aphid, apply Cruiser 5FS at

a rate to achieve between 0.250 and 0.80 milligrams thiamethoxam

per kernel (each

fluid ounce of Cruiser 5FS contains 17.7 grams thiamethoxam).

To provide corn rootworm (including Mexican, Northern, Southern, and Western corn

rootworm) and billbug protection, apply Cruiser 5FS at a rate to achieve 1.25 milligrams

thiamethoxam per kernel (each fluid ounce of Cruiser 5FS contains 17.7 grams


Cotton (Delinted Only)

To provide early season protection of seedlings against injury by cotton aphid, tobacco

thrips, western flower thrips, wireworm, and the suppression of cotton fleahopper and

plant bugs, apply Cruiser 5FS at a rate to achieve between 0.30 and 0.34 milligrams

thiamethoxam per seed (each fluid ounce of Cruiser 5FS contains 17.7 grams thiamethoxam).

Plant Cruiser 5FS-treated cotton seed based on specified planting dates and soil


made by your state agricultural extension agent. In areas that have a


of high thrips pressure or when cotton is grown in North Carolina or Virginia,

use Cruiser 5FS seed treatment followed by a foliar insecticide spray when cotton is

between the 1st and 3rd leaf stage.

Do not apply a neonicotinoid insecticide within 45 days of planting seed treated with

Cruiser 5FS.

Cucurbit Vegetable Group


Chinese Waxgourd

Citron Melon



Edible Gourd (includes hyotan, cucuzza, Chinese Okra, and hechima)

Momordica spp. (includes balsam apple, balsam pear, bitter melon, Chinese cucumber)

Muskmelon (includes true cantaloupe, cantaloupe, casaba, Crenshaw melon, golden

pershaw melon, honeydew melon, honey balls, mango melon,

Persian melon, pineapple melon, Santa Claus melon, and snake melon)


Summer Squash (includes crookneck squash, scallop squash, straightneck squash,


marrow, and zucchini)

Winter squash (includes butternut squash, calabaza, hubbard squash, acorn squash

and spaghetti squash)


To provide early season protection of seedlings against injury by Cucumber Beetle

apply Cruiser 5FS at a rate to achieve between 0.25 to 0.75 milligrams thiamethoxam

per seed* (each fluid ounce of Cruiser 5FS contains 17.7 grams of thiamethoxam).

*Based on an average range of 4,000 to 27,000 cucurbit seeds per pound.

Do not apply a neonicotinoid product (including Actara and Platinum) to cucurbits

previously treated with a Cruiser 5FS seed treatment.

Legume Vegetable Group

Bean (Lupinusspecies) (includes grain, sweet, white, white sweet lupin).

Bean (Phaseolus species) (includes field bean, kidney bean, lima bean, navy bean, runner

bean, snap bean, tepary bean, wax bean)

Bean (Vigna species) (includes adzuki bean, asparagus bean, blackeyed pea, catjang,

Chinese longbean, cowpea, Crowder pea, moth bean, mung bean, rice bean, southern

pea, urd bean, yardlong bean)

Broad bean (fava bean)

Chickpea (garbanzo bean)



Lablab bean (hyacinth bean)


Pea (Pisum species) (includes dwarf pea, edible-pod pea, English pea, field pea, garden

pea, green pea, snow pea, sugar snap pea)

Pigeon pea

Sword bean

To provide early season protection of seedlings against injury by aphids, bean leaf


leafhoppers, leaf miner, Mexican bean beetle, pea leaf weevil, plant leaf


seed corn maggot, thrips, white grub and wireworm, apply Cruiser 5FS at 1.28

fluid ounces per l00 pounds of seed.

It is highly recommended to use Cruiser 5FS with compatible and registered seed treatment

fungicides proven to control seed and seedling diseases. These fungicides must

show safety on treated seed, alone and in combination with Cruiser 5FS.


To provide early season protection of seedlings against injury by aphids, bean leaf

beetle, grape colaspis, leafhoppers, seedcorn maggot, threecornered alfalfa hopper,

thrips, white grubs, and wireworm, apply Cruiser 5FS at 1.28 fluid ounces per 100

pounds of seed. Alternatively, for those who wish to treat on a milligram per seed basis,

apply 0.0756 to 0.1512 mg. a.i. per seed.

It is highly recommended to use Cruiser 5FS with compatible and registered seed

treatment fungicides, like Apron XL and Maxim or ApronMAXX® brand formulations,

proven to control seed and seedling diseases. These fungicides must show safety on

treated seed, alone and in combination with Cruiser 5FS.

Do not apply a neonicotinoid insecticide within 45 days of planting seed treated with

Cruiser 5FS.

Oil Seed Crops (black mustard seed, borage seed, crambe seed, field mustard seed, flax

seed, Indian mustard seed, Indian rapeseed seed, Rapeseed seed, and safflower seed)

To provide early season protection of seedlings against injury by crucifer flea beetles

and wireworms, apply Cruiser 5FS at 10.24 fluid ounces per 100 pounds of seed.

It is highly recommended to use Cruiser 5FS with compatible and registered seed treatment

fungicides proven to control seed and seedling diseases. These fungicides must

show safety on treated seed, alone and in combination with Cruiser 5FS.


Note: Do not use, sell or distribute this product for use on potatoes, within, or into,

Nassau County or Suffolk County, New York.

Cruiser 5FS potato seed treatment is to be used as an integral part of a potato pest

management strategy.

This strategy includes the use of certified seed, proper crop rotation,

insect population thresholds, appropriate control measures, optimal harvest time

for tubers and proper handling of tubers without bruising. Consult your local agricultural

extension agent for more detailed information on insect management practices.

Application Procedure

Apply Cruiser 5FS using only Syngenta approved equipment that is designed to apply

liquid seed treatment products to potatoes. Follow the equipment instructions for

set-up and calibration. Cruiser 5FS may require dilution prior to atomization and

application to potatoes (see equipment use instructions). Ensure that spray nozzles

are properly hooded and shielded to prevent any spray from moving off target. Apply

Cruiser 5FS only in well-ventilated areas. Syngenta Crop Protection will not warranty

the field performance of Cruiser 5FS if the application is made through non-Syngenta

approved equipment. The mixture is applied as a fine spray over the cut or whole seed

tubers. The quantity of water and Cruiser 5FS volume is adjusted based on the amount

of seed moved under the hood. It is mandatory that the equipment be calibrated to

deliver a maximum of 4 fluid ounces of the mixture per 100 pounds of seed consistently.

Applying excess moisture may predispose the seed to rotting, resulting in poor

emergence and stand. Generally, liquid based fungicides (such as Maxim 4FS), can be

applied with Cruiser 5FS, however check compatibility of the fungicides with Cruiser

5FS before use. If inert dust (fir bark, talc, etc.) or a dust-based fungicide is used, apply

the Cruiser 5FS seed treatment before applying the dust.

It is highly recommended to use Cruiser 5FS with compatible and registered seed treatment

fungicides proven to control seed and seedling diseases. These fungicides must

show safety on treated seed.

Use Cruiser 5FS seed treatment to provide protection against injury from Colorado

potato beetles, flea beetles, green peach aphids, leafhoppers, leafminers, potato

aphids, psyllids, and whiteflies. Cruiser 5FS will also control wireworms that feed on

the seed piece.

The expected length of protection is dependent upon the rate used, soil and environmental

conditions and insect pressure. Select the appropriate Cruiser 5FS rate based

upon the history of pest pressure in the region and the length of the growing season.

In general, use the high rate of Cruiser 5FS in the following table for areas where

high insect pressure is expected. Consult your Syngenta representative for information


to your area or region.

Choose the appropriate Cruiser 5FS rate from the following chart, based

upon your seeding rate:

Potato Seeding Rate:

100 lbs. per Acre

Fluid Ounces of Cruiser 5FS

per 100 lbs. of Potato Seed Tubers

16-19 0.11-0.16

20-21 0.11-0.15

22-24 0.11-0.13

25-26 0.11-0.12

27-29 0.11

For seeding rates not covered by the above table, do not use a Cruiser 5FS rate that will

result in more than 0.125 pounds thiamethoxam per acre.

Treated Seed Storage

If the treated seed needs to be stored or held for a few days, make sure that there

is adequate cool air (60°F) movement through the pile of cut seed potatoes at relative

humidity of 85-90%. Do not pile cut and treated seeds above 6 feet in height.

Best results are obtained if potatoes are planted immediately after Cruiser 5FS seed


When transporting cut and Cruiser 5FS treated seed, make sure the seed

is covered.

Rice (dry-seeded use only)

To provide early season protection of seedlings against injury by grape colaspis rice

water weevil, chinchbugs, and thrips, apply Cruiser 5FS at a rate to achieve 0.03 milligrams

thiamethoxam per seed* (each fluid ounce of Cruiser 5FS contains 17.7 grams


Cruiser 5FS is not labeled for use in water seeded rice production.

Do not plant or sow Cruiser 5FS treated rice seed by aerial application equipment.

Do not use treated fields for the aquaculture of edible fish and crustacean.

*Not to exceed 120 lb. seed/Acre Seeding Rate.


To provide early season protection of seedlings against injury by chinch bug, corn leaf

aphid, fire ants, greenbug, seed corn maggot, stored grain insects, wireworm, and

yellow sugarcane aphid, apply Cruiser 5FS at 5.1 to 7.6 fluid ounces per 100 pounds of

seed or 0.062 to 0.093 milligrams thiamethoxam per seed* (each fluid ounce of Cruiser

5FS contains 17.7 grams of thiamethoxam).

*Based on an average of 14,500 sorghum seeds per pound.

Follow planter manufacturer instructions for use of talc or other hopper box additives

at planting.

A closed system must be used for commercial treatment of sorghum seed.


Cruiser 5FS is a seed treatment insecticide that provides early season protection against

injury from sugarbeet root maggot, leaf miners, wireworms, root aphids, white grubs,

spring tails, and beet leaf hopper. Cruiser 5FS protects sugarbeets from beet leaf hoppers

which may spread curly top virus. Thorough seed coverage will offer the best

protection of the seed from insect damage.

Apply Cruiser 5FS at 3.39 to 3.95 fl. oz. (equivalent to 60 to 70 grams a.i. of thiamethoxam

respectively) per unit of sugarbeet seed. A unit of sugarbeet seed is 100,000 seeds.

For protection against Pythium damping-off or Rhizoctonia species seed and seedling

diseases in sugarbeets, Cruiser 5FS may be applied with Apron XL® and Maxim 4 FS

fungicide seed treatments.

Cruiser 5FS may be applied in conjunction with polymers, pelleting materials and seed

coating materials that are approved as food-use inert ingredients by EPA and listed in

40 CFR 180.910-960. These materials must show safety on treated seed. The end product

that combines Cruiser 5FS with labeled fungicides must be tested for seed safety

without any detrimental effects on seed germination or plant stand establishment.

Pre-test the germination of a small sample of seed lot with Cruiser 5FS prior to large

scale commercial application.


To provide early season protection of sunflower seedlings against injury by flea beetle,

stored grain insects, sunflower beetle, and wireworm, apply Cruiser 5FS at 0.25 milligrams

thiamethoxam per seed (each fluid ounce of Cruiser 5FS contains 17.7 grams


It is highly recommended to use Cruiser 5FS with compatible and registered seed

treatment fungicides such as Apron XL®, Dynasty and Maxim 4FS which are proven to

control seed and seedling diseases.

Follow planter manufacturer instructions for use of talc or other hopper box additives

at planting.


To provide early season protection of seedlings against injury by bird cherry-oat aphids,

English grain aphid, greenbug, Hessian fly, and Russian wheat aphid, and to reduce

potential spread of barley yellow

dwarf virus due to aphid vectors, apply Cruiser 5FS at

0.75-1.33 fluid ounces per 100 pounds of seed. At the high rate, Cruiser 5FS will reduce

grasshopper damage in wheat during the early season. For early season wireworm protection,

apply Cruiser 5FS at 0.19 to 0.25 fluid ounces per 100 pounds of seed.


Do not contaminate water, food, or feed by storage, disposal, or cleaning of equipment.

Pesticide Storage

Store in a cool, dry place. Do not store above 90°F for extended periods.

For minor spills, leaks, etc., follow all precautions indicated on this label and clean up

immediately. Take special care to avoid contamination of equipment and facilities during

cleanup procedures and disposal of wastes.

Pesticide Disposal

Wastes resulting from the use of this product may be disposed of on site or at an

approved waste disposal facility. If these wastes cannot be used according to label

instructions, contact your State Pesticide or Environmental Control Agency or the

Hazardous Waste representative at the nearest EPA Regional Office for guidance in

proper disposal methods.

Container Handling (<5 gallons)

Non-refillable container. Do not reuse or refill this container. Triple rinse container (or

equivalent) promptly after emptying. Triple rinse as follows: empty the remaining contents

into application equipment or a mix tank and drain for 10 seconds after the flow

begins to drip. Fill the container 1/4 full with water and recap. Shake for 10 seconds.

Pour rinsate into application equipment or a mix tank or store rinsate for later use or

disposal. Drain for 10 seconds after the flow begins to drip. Repeat this procedure two

more times. Then offer for recycling if available or puncture and dispose of in a sanitary

landfill, or by incineration, or if allowed by state and local authorities, by burning. If

burned, stay out of smoke.

Container Handling (>5 gallons)

Non-refillable container. Do not reuse or refill this container. Triple rinse container

(or equivalent) promptly after emptying. Triple rinse as follows: empty the remaining

contents into application equipment or a mix tank and drain for 10 seconds after the

flow begins to drip. Fill the container 1/4 full with water. Replace and tighten closures.

Tip container on its side and roll it back and forth, ensuring at least one complete

revolution, for 30 seconds. Stand the container on its end and tip it back and forth

several times. Turn the container over onto its other side and tip it back and forth

several times. Empty the rinsate into application equipment or a mix tank or store

rinsate for later use and disposal. Repeat this procedure two more times. Then offer for

recycling if available or puncture and dispose of in a sanitary landfill, or by incineration,

or if allowed by state and local authorities, by burning. If burned, stay out of smoke.


Apron XL®, Cruiser®, Dynasty®, Maxim®, the Syngenta logo, and the CP FRAME

are trademarks of a Syngenta Group Company

U.S. Patent Nos. 5,852,012 and 6,022,871

©2009 Syngenta

For non-emergency (e.g., current product information), call

Syngenta Crop Protection at 1-800-334-9481.

Manufactured for:

Syngenta Crop Protection, Inc.

P.O. Box 18300

Greensboro, North Carolina 27419-8300

SCP 941B-L3N 0909


Printable version of Grasshopper Management Module (PDF)

Managing Grasshoppers in Montana’s Rangeland and Cropland

Kevin Wanner, Assistant Professor, Entomology

Extension Specialist, Cropland Entomology

Department of Plant Sciences & Plant Pathology

Montana State University

Grasshoppers are common pests in Montana particularly in the central and eastern

regions. During 2010 - 2012, however, Montana has been facing a potential outbreak in

size not witnessed since the mid 1980’s. Managing grasshoppers during severe

outbreaks can be challenging. Ranches may have to consider alternative sources of

forage. At severe outbreak levels even repeated insecticide applications may not

salvage spring planted crops that are surrounded by grassland.

Rangeland: A total of 15-20 grasshopper nymphs per square yard is considered an

economic threshold for treatment. At these densities grasshoppers can result in 200 –

500 pounds of lost forage per acre of rangeland, depending on their duration and

conditions such as precipitation. Reduced Agent and Area Treatment strategies

(RAATs) can be used to control grasshoppers in rangeland. USDA research has

demonstrated that RAATs, a “skip pass” approach that also uses lower rates of

insecticide, can achieve 80 to 95% control (compared to 85-99% control with complete

blanket coverage at the full insecticide rate) at a lower cost. RAATs can be applied by

ground or air. The insecticide dimilin is most commonly used in large-scale grasshopper

spray operations. Dimilin is an insect growth regulator that is only effective against

juvenile insects that are molting. It is NOT effective against adult insects that no longer

molt, so timing is critical. Ideally the majority of grasshoppers should be in the 3rd instar

stage during treatment. Commercial honeybee colonies are often placed on ranchland.

A benefit of dimilin’s mode of action is that it is relatively safe to adult honeybees.

Spring Wheat: Grasshoppers are notorious for their ability to move into cropland from

surrounding grassy areas; cropland surrounded by grass is particularly at risk. The

treatment threshold for immature nymphs is different from thresholds for adults, and

also depends on whether the grasshoppers are within the field or around the edges.

The attached High Plains IPM Guide contains a table for thresholds in spring and winter

planted wheat. Crop protection is typically achieved by applying a boarder treatment of

insecticide to keep the grasshoppers from entering the crop. A border width of 150 feet

surrounding the crop may be adequate for control, but if grasshopper densities are high,

control may require up to a 1/4 mile border treatment where ground applied RAATs can

be considered. Under extreme pressure, control may be difficult and multiple border

treatments may be required. Border areas and crop margins should be monitored after

treatment to ensure that grasshoppers do not re-enter the field. Insecticide baits can

also be effectively used but USDA research has found that the effectiveness of

insecticidal baits can depend on grasshopper densities. Baits are not recommended

when grasshopper densities are higher than 30-40 per square yard.

Winter Wheat: Emerging winter wheat can be particularly vulnerable to damage by

grasshoppers. The larger adult stage grasshoppers are more difficult to control and can

move into emerging winter wheat fields from surrounding grassy areas. Treatment

thresholds for emerging winter wheat are lower, 3-7 per square yard within the field, or

11-20 per square yard around the margin probably requires treatment. Border

treatments applied as insecticidal sprays or seed treatments are the main

recommendation for protecting emerging winter wheat. Typically, spraying 150 feet

beyond the edge of the crop or 1-2 passes with treated seed around the perimeter of

the field is a sufficient border. Adult grasshoppers are more difficult to control, and the

higher end of the label rate is recommended. If grasshopper populations are very high

they are difficult to control, borders up to ¼ of a mile and repeated applications may

need to be considered. When applying border sprays, timing is important. Border sprays

beyond the edge of the crop need to be applied just before the wheat emerges; if it is

applied too early there may not be enough residual, it is applied too late, the damage

may have already occurred. Systemic seed treatments eliminate the timing concern, but

systemic insecticides require feeding to be active, but damage should be slowed

considerably. Commonly used insecticides are listed in the attached High Plains IPM

pest notes.

Treatment Thresholds: The number of insects that require treatment to prevent

economic damage can depend on factors such as the weather, crop health and crop

stage. For example, damage to rangeland by the same density of grasshoppers is more

severe during drought periods. Fewer grasshoppers can cause economic damage to

crops if they are feeding at sensitive developmental times. In some cases grasshoppers

in spring wheat crops can clip the developing heads, for example. One research study

reported that grasshoppers in lentil fields during flowering feed preferentially on the

flowers and developing pods, and a treatment threshold of only 2 per square yard was

recommended. Therefore treatment thresholds should be used as a sound guide

tempered with experience and observations of damage.

Additional information can be found on the USDA ARS Sidney grasshopper website,

http://www.sidney.ars.usda.gov/grasshopper/. The High Plains IPM Guide website,

http://wiki.bugwood.org/HPIPM, provides detailed information on sampling, thresholds

and management. RAATs brochures and management guides are provided as

attachments below.

Printable version of Grasshopper Scouting Module (PDF)

Scouting Grasshoppers in Rangeland and Cropland

Kevin Wanner, Assistant Professor, Entomology

Extension Specialist, Cropland Entomology

Department of Plant Sciences & Plant Pathology

Montana State University

Vigilant scouting is important during grasshopper outbreaks. Egg hatch typically begins

sometime during May and can continue throughout the summer depending on the

weather and species of grasshopper. Small newly hatched grasshoppers are more

difficult to see due their size and require more careful attention. Grasshopper activity

occurs earlier and can be concentrated on warmer south facing slopes. As

grasshoppers get larger, particularly when winged adults are present, it can be more

difficult to estimate their numbers. Early in the morning when its cool grasshoppers are

less active and it can be easier to estimate their numbers. Later in the season, when

winter wheat is planted, most of the population can be winged adults and damaging

populations can fly in with little notice.

Grasshoppers tend to move into crops from surrounding grassland and damage is more

pronounced on crop edges. In some cases weeds can attract grasshoppers into fallow

fields before winter wheat is planted. Cropland intermixed with grassland, such as

Conservation Reserve Program (CRP) areas, is at higher risk of continued invasion and


The square foot method of surveying grasshoppers is used by USDA-APHIS to estimate

grasshopper densities in rangeland and produce hazard maps. With practice it is

considered accurate. The number of grasshoppers in a one square foot area is

estimated visually and randomly repeated 18 times while walking a transect. The total

number of grasshoppers is tallied and divided by two to give the number per square

yard. Alternatively, since it is difficult to estimate the number of grasshoppers per

square yard when population densities are high, sweep nets can be used. Four 180-

degree sweeps with a 15-inch diameter sweep net is considered equivalent to the

number of adult (or nymph) grasshoppers per square yard (NDSU Extension).

A total of 15-20 nymphs per square yard (correlates to about 10 adults) is considered

the economic threshold for rangeland. However, the actual threshold in can depend on

weather, the same number of grasshoppers can cause more damage to rangeland

during a dry period. A table with estimates of forage loss for different densities of

grasshoppers is provided below. Also provided below is a table with economic

thresholds for spring and fall planted grains. Again, actual damage can depend on crop

stage and condition and treatments may be required at lower numbers if there are signs

of economic damage.

Treatment thresholds for grasshoppers infesting grains (source: High Plains IPM Guide,


Table 1. Spring treatment guidelines for immature and adult grasshoppers in spring wheat (modified from

University of Minnesota information).

Immatures/yd2 Adults/yd2

Rating Margin Field Treat? Margin Field Treat?

Nonthreatening <25 <15 No <10 <3 No

Light 25-35 15-25 No 10-20 3-7

Yes, if there is potential for

head clipping

Threatening 50-75 30-45

Depends on prices,

crop condition

21-40 8-14

Yes, if there is potential for

head clipping

Severe >100 >60

Yes, monitor for


>41 >15

Yes, consider wider border

treatments and

Table 2. Fall treatment guidelines for adult grasshoppers in winter wheat (modified from University of Minnesota



Rating Margin Field Treat?

Nonthreatening <10 <3 No

Light 10-20 3-7 Yes

Threatening 21-40 8-14 Yes, consider wider border treatments

Severe >41 >15

Yes, use wider border treatments and

monitor for retreatment.

Printable version of Bark Beetle (PDF)

Bark Beetles

Are Your Trees at Risk?

Many species of bark beetles are causing widespread tree mortality throughout the Intermountain West. Although sometimes viewed by hu­mans as catastrophic, outbreaks of native forest insects are natu­ral events. Native insects and the plants they use for food and reproduction have evolved togeth­er. Unlike some introduced pests, native insects kill individual trees but do not threaten the ex­istence of an entire plant species. Native insect outbreaks only pose a problem when they con­flict with human resource values for a particular area (i.e., recreation, aesthetics, wildlife habitat, wood production, property values, etc). A tree in the wilderness is not subject to the same human values as a tree in your backyard.

Bark beetle populations have increased in forested areas of the western U.S. An abundance of larger-diameter trees in dense stands across broad landscapes and periodic drought have caused this increase in bark beetle populations.

Bark beetles causing widespread mortality in the forests of the Intermountain West are all native. Principal species include: mountain pine beetle, spruce beetle, Douglas-fir beetle, western pine beetle, fir engraver, western balsam bark beetle, pine engraver, and pinyon ips.

How can something so small

kill something so big?

These insects are small, brown and often difficult to see since most of their life is spent under the bark. Individual bark beetles are about the size of a grain of rice. In low numbers (latent populations) bark beetle populations are often associated with newly dead, dying or stressed trees caused by wind, snow, lightning, disease, feeding by other insects, or damage created by human activities. Single-tree and small-group mortality widely dispersed over the landscape is associated with these low level populations.

Beetle populations rise as susceptible hosts become more abundant. Disturbance (i.e. drought, windthrow, fire or insect defoliation) often initiates this population increase. Over large susceptible landscapes abundant tree mor­tality can occur, often affecting most, if not all, of the overstory trees.

When beetle populations are low, healthy and vigorous trees produce sufficient resinous pitch to drown or “pitch out” attacking adult in­sects. As trees become stressed, pitch production declines and the number of successful beetle at­tacks increases. During bark beetle outbreaks, however, even healthy trees are overwhelmed by many adult beetles “mass attacking” the tree. In addition to damage created by the beetles and their offspring, many beetles also harbor fun­gi that further limit the tree’s ability to transport needed nutrients and water.

DOUGLAS-FIR mortality (outbreak)

A Douglas-fir beetle

A “pitchout”

A “pitchout”

This publication is a collaborative effort between Forest Health Protection and National Forests to inform the public about tree-killing bark beetles, emphasising the northern Rocky Mountain and Intermountain regions (Utah, Ne­vada, western Wyoming, Idaho and Montana).

This information will assist you in identify­ing probable causes of tree mortality and determining your treatment options. It also lists contact information for your respective State and Federal Forest Health Specialists and other sources of information available to the public.

Fading trees attacked by bark beetles

Does this affect you? Look inside

Are my trees at risk?................................page 2

Have my trees been attacked?..........page 5

How to prevent Attacks.........................page 6

What is a bark beetle?............................page 8

What are land managers doing?......page 10

What causes similar attacks?............page 11

Who Should I Contact?............................page 12





Forest Health Protection – Intermountain West & Northern Rocky mountains

Are Your Trees atRisk to Bark Beetles?

WhatShould You Do?

Step 1: Identify Your Trees

The first step in determining whether or not your tree is susceptible to insect attack is to know what species of tree you have. The following lists are the principal evergreen species found in the Intermountain West and Northern Rocky Mountain regions.

Most pines have more than one needle attached to the tree together in a “bundle”. The number of needles per bundle is often important in determining the pine species.

Pines (native):


Needles are two per bundle, 1-3" long. The small ¾-2" long cones have very short stalks and stay attached to the tree for many years. Cones feel prickly.

Natural Range: ID, MT, WY, northern UT, spots along the Sierra Nevada Range in NV.

PINYON (Colorado and Singleleaf)

Colorado pinyon, found mainly in Utah have two, 1-2" long nee­dles per bundle. Singleleaf pinyon, found mainly in Nevada, have one sharp, rounded needle per bundle, >1" long. Cones are not spiny.

Natural Range: Colorado pinyon in UT; Singleleaf pinyon in NV, western edge of UT, scattered spots in southern ID.

SIngleleaf pinyon

Foliage with MALE and female CONES

Closed and open cones

Colorado pinyon

5-NEEDLED (e.g. limber, whitebark, and western white pines)

Several pine species with 5-needle bun­dles are native to the Intermountain West, but Limber is the more commonly planted species around homes. Needle length ranges from 1.5-4". Cones vary.

Natural Range: various throughout In­termountain West.

PONDEROSA (and Jeffrey)

Ponderosa needles are 2-3 to a bundle, ranging from 3-10" in length. Cones are 2-6" long and prickled. Jeffrey pine (3-needles) is found along the Sierra Nevada’s, overlapping with ponderosa pine’s broad range. Jeffrey generally has larger, stouter cones (5-9") with incurved spines (pokey ponderosa; gentle Jeffrey).

Natural Range: ID, MT, UT, spots in eastern NV and the Sierra Nevadas, isolated spots in WY.



oPEN PONDEROSA CONES 3 Forest Health Protection – Intermountain West & Northern Rocky mountains

Pines (exotic):

Austrian pine


These European pines have 2-needles per bundle, 1.5-3" and 3-6" longs, respectively. Scotch cones are smaller (1.5-2" long) than Aus­trian cones (2-3"). Cones of both species are not spiny (vs. ponderosa). Scotch pine is noted for the strong orange coloration of the bark.

Natural Range: As exotic species there is no native range but they can be found planted throughout the Intermountain West.

Scotch pine

Firs and spruce have only one needle (no ‘bundles’) but the shape of that needle can differ by tree species.

SPRUCES (native):

FIRS (native):

Subalpine fir

The short (1-1.5"), single, flat needles also have rounded tips but are thick at their base (vs. white fir). The dark purple cones (2.25-4" long) are borne upright on the up­per branches and are not dropped.

Natural Range: ID, western MT, west­ern WY, UT, spots in northern NV.

WHITe fir

The 2-3" long, single, flat needles nar­row to a stalk at their base and have round­ed tips (vs. sharp spruce or notched grand fir). The needles tend to curve upward, leav­ing few needles below the stem. The green­ish purple or yellow cones (3-5"), found in the upper branches, point up and are not dropped. Rather, they fall apart on the tree (vs. Douglas-fir cones that drop off).

Natural Range: UT, eastern NV, south­east corner of ID.

Engelmann and Blue Spruce

Single needles are square and sharp, leaving ‘bumps’ on the small twigs when they fall off. Blue spruce needles tend to be stiffer and sharper than Engelmann needles. Cones hang down, measuring 1- 2.5" in length for Engelmann and 2.5-4" for blue. In the wild, blue spruce prefers moist stream edges.

Natural Range: Engelmann spruce in ID, MT, WY, UT, and NV; blue spruce in UT and WY.




Upright cones stay on branches


The single, flat needles of grand fir are 1.25-2 inches long and distinguished by having a notched end. Needles tend to grow out to the sides giving the branch­lets a flattened appearance. Cones are also 2-4" long, green-brown in color, and extend up­ward.

Natu­ral Range: north­ern two-thirds of ID, north­west edge of MT.


Although not a true fir species, Douglas-fir is similar to other firs in having short (~1"), single, flat needles. Needles have rounded tips like white and subalpine fir, and are narrow at their base like white fir. However, the 3" long cones hang down. The cone scales have a distinct shape resembling the tail and back legs of a mouse.

Natural Range: ID, MT, WY, UT, and scat­tered spots in NV.

Young cones

Upright cones stay on branches




  • Kuhns, Michael. 1998. A guide to the trees of Utah and the Inter­mountain West. Utah State University Press, Logan, UT
  • National Audubon Society. 1996. Field Guide to North American Trees. A. A. Knopf, NY
  • Watts, Tom. 1985. Rocky Mountain Tree Finder. Nature Study Guild, Rochester, NY


Foliage and buds 4 Forest Health Protection – Intermountain West & Northern Rocky mountains

Step 2: Determine Your Trees’ Susceptibility

The susceptibility of an individual tree is of­ten described differently than the susceptibili­ty of a stand of trees. When there is a group of trees (a stand), a tree may be killed yet the over­all stand may look and function much as before. In an urban setting, however, individual trees are very important for aesthetic or other urban land­scape values.


Stressed trees produce less pitch reduc­ing the tree’s ability to prevent successful bark beetle attacks. Tree stress can be caused by hu­man activities (construction, paving, excavating, etc) or by natural causes (drought, wind, light­ning, other insects or disease agents etc.). Visual symptoms associat­ed with tree stress of­ten include sickly look­ing tree crowns.

Not all stressed trees are at­tacked by beetles, particular­ly when bark beetle populations are low. However, during bark beetle outbreaks, even healthy trees can be successfully attacked.


Dense stands composed of single-species, larger-diameter trees are most susceptible to bark beetle attacks; less-dense stands are gener­ally more vigorous and have higher pitch pro­duction. Stands of trees stressed by prolonged periods of drought or by defoliation, disease or other damage (windthrow, fire, etc) are especial­ly susceptible. Overall, stands that have mul­tiple age classes, species diversity and reduced tree densities are less susceptible to bark bee­tle attacks and associated impacts. Even dur­ing a bark beetle outbreak not all trees in a stand are killed.


Some bark beetles are species-specific tree killers. For instance, Douglas-fir beetle only at­tacks Douglas-fir trees. However, other spe­cies like mountain pine beetle will attack several species of pines.

Lodgepole, ponderosa, five-needle pines and other native and introduced pines: Most of our introduced and native western pines, with the exception of Jeffrey pine, are susceptible to mountain pine beetle attacks. Jeffrey pine is at­tacked by Jeffrey pine beetle which is very sim­ilar to mountain pine beetle. Pines susceptible to attack my mountain pine beetle are often >8 inches in diameter at breast height and weak­ened by drought. If populations of this insect are high, fire scorched trees are also suscepti­ble to attack. Windthrown or downed pine trees are rarely attacked by mountain pine beetle, but are often attacked by pine engraver. In standing trees pine engraver can be found attacking trees alone or in combination with other bark beetles, particularly during periods of drought. Pondero­sa pine (west of the Continental Divide) weak­ened by old age or other stressors (e.g. compe­tition, lightning, root disease) are susceptible to western pine beetle. Ponderosa pine in southern Utah and Nevada may be atacked by roundhead­ed pine beetle.

Singleleaf and Colorado pinyon pines: Al­though several species of bark beetles will attack pinyon pine, the most notable for causing wide­spread mortality is pinyon ips. Trees stressed by drought, defoliation and fire are very susceptible to attack. Prolonged periods of drought are of­ten the primary stress responsible for landscape level mortality associated with this bark beetle. However, slash piles created by thinning or con­struction of fuel breaks can increase local popu­lations of this insect to outbreak levels.

Engelmann and blue spruce: Engelmann spruce is the preferred host for spruce beetle; although during outbreaks of this insect blue spruce will also be attacked and killed. Spruce beetle prefers larger-diameter trees (>16 inch­es) but will kill trees as small as 5 inches in di­ameter during an outbreak. Spruce beetle popu­lations can build quickly in green downed trees resulting from windthrow or avalanche. If there is sufficient downed material allowing popula­tions to build to outbreak levels, emerging adult beetles will attack surrounding live trees.

Douglas-fir: Douglas-fir are attacked and killed by Douglas-fir beetle. The insects pre­fer trees >14 inches in diameter; especially those growing in dense stands or weakened by drought, fire, root disease or defoliation. Out­breaks of this insect are often associated with fire scorched trees or an abundance of recent downed green material. Smaller trees, <8 inch­es in diameter may be killed by Douglas-fir pole beetle.

White and grand fir: Fir engraver is the principle bark beetle associated with these tree species. Larger diameter trees are preferred, but during periods of stress caused by drought or de­foliation, trees as small as 3 inches in diameter are also killed. Attacks by this insect will not al­ways result in tree mortality; topkill and individ­ual branch mortality are also common.

Subalpine fir: Although fir engraver will also attack subalpine fir, particularly where it is intermixed with white and/or grand fir, most bark beetle attacks are associated with western balsam bark beetle. Populations of this insect are attracted to disease-stressed trees. Windthrown green trees are also preferred habitat for this bark beetle. Often a complex of organisms is re­sponsible for tree mortality including bark bee­tles, root disease, and drought. Landscape level mortality caused by this bark beetle usually cor­responds to extended periods of drought.

A dense stand with trees competing for resources

A thinned stand with a diversity of tree ages

Crown differences

between a healthy (left) and stressed (right) tree5 Forest Health Protection – Intermountain West & Northern Rocky mountains

Step 3: Determine if Your Trees Have Been Attacked

Many tree symptoms and associated signs of bark beetle attack are similar regardless of the tree or beetle species involved. Some of the most common symptoms and signs are de­scribed below.


As bark beetles bore into living trees, tree sap or pitch may be exuded from the entry hole as the tree attempts to drown the beetle. Beetles may push this pitch out their entry hole as they continue construction of their galleries, leav­ing small sticky tubes visible on the outside of the bark.

Not all tubes, however, indicate a successful attack. In some cases trees are successful in their defense and the beetles are flushed out. Unsuc­cessful-attack pitch tubes are often a light cream color. However, pitch tubes created when beetle attacks are successful are often reddish in color due to presence of sawdust in the pitch produced as beetles bore through the tree bark.

Attacks by mountain pine beetle on lodge­pole, ponderosa and other pines, or attacks by Jeffrey pine beetle on Jeffrey pine, are often de­tected early due to the presence of these highly visible tubes. Occasionally, trees produce little pitch or attacks are so high up on the tree bole that tubes are not readily visible.


Whether or not pitch tubes are visible, pres­ence of boring-created sawdust around the base of the tree or in bark crevices is a good indica­tor of successful beetle attack. Boring dust is the best indicator to use when trees are too stressed to produce pitch (dry attacks) or when attacks occur higher up on the tree bole. This is often the case for moun­tain pine beetle or pinyon ips at­tacks on pines in areas under drought (dry at­tacks) and for Douglas-fir bee­tle attacks on Douglas-fir and spruce beetle attack on Engle­mann spruce (high attacks).

Sawdust may also be created by carpen­ter ants and ambrosia beetles. However, both groups bore directly into the heartwood creating a white boring dust.


Woodpeck­ers and other birds foraging for beetle larvae and adult beetles will often flake off bark lay­ers, leaving piles of bark flakes around the base of infested trees. These bark flakes are particularly visible during the winter months against the white snow. Several species of pine and Engelmann spruce are frequently de­barked as these avian bark beetle predators feed.


Fading tree crowns are a good indicator of successful bark beetle attack. Depending on the tree species, needles will turn yellow, yellow­ish-green, sometimes orange and later red before they drop to the forest floor. Needle discolor­ation generally occurs within one year of suc­cessful attacks.

Not all tree species will fade at the same rate following bark beetle attack, nor will all trees of the same species fade simultaneously. The speed of fading depends partly on the health of the tree prior to attack, especially its water stress level. For example, pinyon pines attacked by pinyon ips during hot dry summers may fade within 3-4 months while subalpine fir attacked by western balsam bark beetle may fade in one year and healthy Douglas-fir attacked by Doug­las-fir beetle may take 2-3 years to complete­ly fade.

Trees with red needles indicate that beetles have emerged and the tree is no longer a threat to surrounding uninfested trees. However, trees with fading needles that appear yellowish-green or yellow usually have some life stages of the bark beetle present, preparing to emerge in the near future.


Trees may exude pitch for a number of rea­sons not related to bark beetles. Where pitch tubes are usually discrete, popcorn-shaped mass­es of pitch, pitch streamers are more of a long ‘drip’. Pitch streamers may be created when true firs are attacked by fir engraver or western bal­sam bark beetle, and occasional­ly when Douglas-fir are attacked by Douglas-fir bee­tle. Although pitch streamers can be a sign of bark bee­tles, they should not be used as the only indicator of a successful bark beetle attack.


Removing the outer bark in areas of the tree where beetles have attacked will: confirm an at­tack, determine success or failure of the attack, and identify which beetle is responsible for the attack. Each beetle species or species group (i.e. Ips species) has a signature gallery pattern. These specific patterns are described in ‘What is a bark beetle’ (pg 8+). Within successful galler­ies you will often find adult beetles laying eggs in the gallery or larvae feeding or pupating. Unsuc­cessful attacks will have incom­plete galleries and often have galleries filled with pitch. How­ever during initial stages of a bark beetle attack, the galleries are also incomplete.

Red boring dust

on tree bark

Woodpecker feeding

Pitch streaming

Pitch tubes

stages of crown fade

Photo by W. Ciesla, Forest Health International

UNSUCCESSFUL GALLERY FILLED WITH PITCH 6 Forest Health Protection – Intermountain West & Northern Rocky mountains

Step 5: How to prevent Bark Beetle attacks

Preventing successful bark beetle attacks is key to protecting uninfested trees. Once insects have entered the bark there are no effective treat­ments to keep the tree alive. Steps you can take to prevent successful attacks on uninfested trees include:

  1. Remove all currently infested trees.
  2. Always remove, chip or burn recentl­windthrown trees or wood debris that’s >4 inches in diameter. Larger pieces of wood provide a more abundant food source for the beetles and produce more of the adults.
  3. Avoid damaging the bark or root system of standing green trees.
  4. Initiate thinning treatments to reduce stand densities, leaving a mix of age classes, tree species or both. Thin­ning reduc­es competi­tion between trees for lim­ited sun, water and nutrients. Re­maining trees are better able to produce pitch used in the trees defense against bark beetle attacks. A mix of age classes and tree species reduces the stands susceptibility to attack and impacts caused by bark beetle outbreaks. Contact your local State Forester’s office for assis­tance (pg. 12).
  5. Increase age and species diversity to enhance stand resistance to bark beetle attacks, and reduce the effects of tree mortality when at­tacks occur.
  6. Preventative insecticide treatments offer ex­cellent single-tree protection if applied prop­erly. Several formulations of carbaryl and pyrethroids are registered for bark beetle ap­plications. There are no effective or registered insecticides for some species of bark beetles such as fir engraver and western balsam bark beetle.

Step 4: How to Treat Trees That Have Been Attacked

Signs of successful bark beetle attack (bor­ing dust, pitch tubes, etc) that occur on more than half of the tree’s circumference general­ly indicate imminent tree mortality. There are no chemical insecticides shown to prevent tree mortality once adult beetles have penetrated the outer bark. If less than 50 percent of the tree circumference is infested (strip attack), preven­tive treatments may successfully protect the un­infested portion of the tree bole.

Sanitation practices to suppress popula­tions include removing the infested tree, de­barking the tree bole, and chipping or burn­ing the wood. Cutting the tree into firewood lengths may not result in bark beetle mortali­ty, especially if the material is shaded. Howev­er, other treatments may help dry out material before beetles can mature. For example, infest­ed lengths of wood can be moved to sunny lo­cations and rotated weekly, or the bark can be fully or partially removed to expose the phloem to open air. Use of plastic wrapping or tarps over infested material is not a recommended treatment method.

Infested material needs to be addressed before new beetle emerge. Because some bark beetle species have multiple generations per year (i.e. western pine beetle and ips spe­cies) you may have little time for treatment. For example, 35 days may be all that’s re­quired for pinyon ips or pine engraver to complete their lifecycle.

When needles turn reddish-brown in color, most adult beetles have left the tree. Spruce beetle may be the exception, since a portion of the population requires two years to complete its life cycle. There may be oth­er beetles, borers and larvae in the tree but these are usually secondary insects or in­sect predators and pose little threat to residu­al green trees.

Trees with reddish colored needles or those completely void of needles can be used for firewood or left standing as wildlife trees. However, dead trees that present a hazard to existing structures or could endanger humans should be removed before they fall.

Chipping slash

If enhancing wildlife habitat interests you, con­sider keeping dead trees on your forested lands. Standing dead trees in a forest are called “snags” and many species of wildlife depend on snags for their survival.

Owls, hawks, and eagles use snags to perch and to support their nests. Cavity nesters such as woodpeckers, mountain bluebirds, and chickadees nest in the snag cavities.

Chipmunks, squirrels, and other mammals use snags as homes. Bats use areas under loose bark for roosting. Fungi, mosses, and lichens common­ly grow in the decaying wood of a snag.

Insects chew through the decaying wood, cre­ating tunnels and chambers. Moths and ladybird beetles, and many species of reptiles and amphib­ians, hide under the bark of snags.

With so many animals and plants living on and in a dead tree, other animals frequently come there to feed. For example, many species of wood­peckers depend on snags to provide insect larvae for food.

If a tree on your private land does not have the potential to endanger persons or property, please consider leaving it standing for our animal friends!

Thinned pine stand

Dead Trees

are “Home”

to Many


Creatures 7 Forest Health Protection – Intermountain West & Northern Rocky mountains

Chemical Treatments


  • MCH for Douglas-fir beetle: MCH (one-methy-cyclo-hex-3-one) is a chemical used by Douglas-fir beetle to communicate. This pheromone tells dispersing adult beetles that a tree is fully occupied and to look elsewhere for another host tree. The pheromone has been commercially synthesized and is available in small bubble caps that are easily stapled to the tree bole prior to beetle flight in early spring. These are slow release cap­sules that distribute the repellant pheromone over the flight period. Application rates should be 30-40 bubble caps per acre for area protection or 2+ caps per tree for single tree protection. See ‘Using MCH to Protect Tees and Stands from Douglas-fir beetle In­festation’ at http://www.fs.fed.us/r1-r4/spf/fhp/publications/MCH_brochure/MCH_online. pdf.
  • VERBENONE for mountain pine beetle: Verbenone (4,6,6-trimethylbicyclo[3.1.1]- hept-3-en-2-one) is the repellant pheromone for mountain pine beetle. This pheromone is also available commercially. Recommended dosage is 2+ pouches per tree for indi­vidual-tree protection, or in lodgepole pine, 20-40 pouches per acre for area treatment. Application prior to summer beetle emergence is necessary. Verbenone treatments are generally deployed in sites where insecticide application is not feasible. Effectiveness of the verbenone treatment varies depending on beetle population pressure, number of currently infested trees and other stand conditions. Annual removal, debarking or chip­ping of infested trees from the verbenone treated site is recommended. Research stud­ies are currently being conducted to improve the formulation by adding additional re­pellents to enhance treatment effectiveness.
  • Contact your e forest health specialist(page 12) for technical ad­vice on administration of these treatments and to determine if financial assistance is available.


  • Carbaryl – Flowable formulations of this insecticide are registered and effective for several bark beetle species (mountain pine beetle, Jeffrey pine beetle, western pine beetle, spruce beetle, and ips species). These are preventative sprays applied to the tree bole before trees become infested. Generally, insecticide treatments are only used on high-value trees and applied by licensed pesticide applicators. All tree bole surfaces must be treated to the point of run-off including the trees root collar. Spray height var­ies from 30-50 feet depending on tree height. Although the label indicates annual treat­ments are necessary, research has shown that properly treated trees remain protect­ed for 18-24 months. our State orest Health Specialist can assist you with treatment recommendations (page 12), and your State Department of Agriculture can assist in finding licensed pesticide applicators.
  • Other Insecticides - Although registered pyrethroids are effective preventative treat­ments for some species of bark beetles, applications are generally required annually.
  • Systemic Insecticide treatments – Systemic insecticides applied as a soil drench or delivered directly into the trees bole have not been shown to be effective against most of our western bark beetles. However, with some exceptions, tree injections using em­amectin benzoate may be effective against western pine beetle.

Pesticides used improperly can be injurious to humans, animals, and plants. Fol­low directions and read all precautions on the label. Consult your local county agricul­ture agent or State extension agent about restrictions and registered uses of particular pesticides.

MCH bubble cap

Verbenone pouch

Carbaryl application8 Forest Health Protection – Intermountain West & Northern Rocky mountains

WhatisaBark Beetle?

Bark beetles are small (≤1/4-inch long), hard bodied beetles that bore through the tree’s protective outer bark to lay their eggs in the living tissue underneath. Following adult egg-laying, the develop­ing larvae feed on this living tissue, further disrupting nutrient and water flow within the tree. Egg-laying and feeding galleries created by adult beetles and their larvae are unique for each species of beetle. Note that all bark beetle species described in this brochure are native insects.

Feeding larvae girdling tree

Mountain (and jeffrey) pine beetleS

Mountain pine beetle attacks most native and introduced pine species, except Jeffrey pine which is attacked by the very simi­lar Jeffrey pine beetle. Occasionally spruce are attacked, especially when mixed in a stand of host pines. Periodic mountain pine beetle out­breaks kill millions of pine trees throughout for­ests of western North America, making it one of the West’s most important bark beetles.

Beetle populations can reach outbreak pro­portions on susceptible landscapes during pro­longed periods of drought. Trees as small as 4-5 inches in diameter may be attacked and killed during outbreaks, although few to no adult bee­tles are produced. In times of low populations, attacks are confined to trees stressed from over­crowding, disease, defoliation, injury or old age. Downed hosts trees are rarely attacked by this insect.

Successfully attacked trees can have faded foliage as early as 4-5 months following infesta­tion, but generally fade 8-10 months following attack. Emerging adult beetles often begin dis­persing in late June to mid-July with adult flight continuing into September. However, these dates may vary depend on elevation, latitude, and lo­cal weather.

Adult beetles are brown to black in color and about 1/4 inch long with a rounded rear end. The larvae are yellowish white, legless grubs with black heads found within feeding tunnels under the outer bark. The egg-laying gallery created by the female adult beetle is straight and vertical on the tree bole. Gallery length can be 3 feet or more. At the bottom of the gallery is a distinctive “J” shaped crook. Eggs are laid alter­nately along the walls of the egg laying gallery.

Douglas-fir beetle

The only host for this bark beetle is Douglas-fir. Outbreaks are often associated with trees that are windthrown, fire scorched or defoliated. Unlike mountain pine beetle, outbreaks are generally confined to smaller areas with tree mortality generally rang­ing from a few to several hundred trees. Out­breaks are also often of shorter duration.

Although the beetle prefers larger host trees, it will attack and kill trees of many sizes. Trees <8 inches in diameter, however, are more com­monly at­tacked by Dougles-fir pole beetle. Dense stands of suscep­tible hosts spread over large land­scapes can result in widespread mortality.

Adult dispersal can occur from April through August depending on the site. Approximately 10 months after a suc­cessful mass attack, the tree’s needles begin to turn yellowish-green. During drought periods, fading can occur within 4-5 months.

Adults are brown to black and about 1/4 inch long with a rounded back end. Larvae are whitish, legless grubs with brown heads found in the galleries under the bark. The egg-laying gallery is usually about 8-10 inches long with a small angled “J” at the bottom portion of the gallery. The female lays several eggs along one side of the egg gallery before alternating to the opposite side of the gallery to lay several more, repeating the pattern several times.

Spruce Beetle

This bark beetle prefers Engelmann spruce, but will attack blue spruce when populations reach outbreak levels. Even during out­breaks, most blue spruce will survive. Outbreaks typically be­gin in ar­eas of wind-thrown trees, with adult beetles dis­persing to ad­jacent stand­ing trees. Widespread tree mortality can occur in En­gelmann spruce dominated landscapes. Infested trees fade (needles turn a yellowish-green) ap­proximately one year following mass attacks.

Spruce beetle can have a one or two-year life cycle. Adult beetles are 1/4-inch long, with reddish-brown or black wing covers. Larvae are yellowish white, legless grubs found under the outer bark. Spruce beetle egg galleries average 6-8 inches in length. Eggs are laid alternately along the gallery with larvae feeding gregarious­ly outward in all directions.

Mountain pine beetle


Spruce beetle galleries

Douglas-fir beetle galleries 9 Forest Health Protection – Intermountain West & Northern Rocky mountains


Although in the same group as the previous beetles, this native bark beetle tends to be less aggressive, generally attacking individual large, overmature ponderosa pines. Often these trees have been hit by lightning, have root disease, suffer from drought, or are otherwise stressed. However, they can cause patches of mortality in dense stands of medium-sized trees. During periods of prolonged drought, insect population can reach outbreak levels. Note that this beetle is not found east of the Continental Divide.

Adult beetles are dark brown to black and slightly smaller than some of the other bark beetles, ranging from about 1/8-1/5 inch long. Adults create a distinctive random serpentine egg gallery pattern under the bark. Larval galler­ies are rarely seen since larvae inhabit the thick, corky outer bark during most of the year.

This bark beetle species can produce two generations per year depending upon weather conditions. Beetles begin attacks in late spring, continuing until colder weather inhibits further development and spread. Trees attacked in early summer may fade before adult beetles emerge in the fall. Trees attacked in September by the sec­ond generation of beetles, usually fade the fol­lowing spring.


Most native bark bee­tles in the “ips” group are not aggressive tree killers. Rather, they tend to at­tack recently dead, damaged, or stressed trees. Pinyon pine trees, however, are often found in areas prone to water and heat stress. During drought periods, adult beetles overwhelm weak­ened trees 3 inches in diameter and larger. Out­breaks can affect large landscapes of suscepti­ble hosts.

Adult beetle attacks begin early in the spring and can continue through early fall. Two or more generations are produced annually. Be­cause of multiple generations, the insect can spread rapidly when conditions are favorable.

Pinyon ips are about 1/8-inch long, with an indented backside (versus a rounded back end) and small spines that are typical of all Ips spe­cies. Gallery patterns of most ips are similar, of­ten a Y- or H-shape, with a larger mating cham­ber from which the separate egg galleries ra­diate. Larva and beetles overwin­ter under the bark where they con­sume large patches of inner bark. Wood bor­ers often in­fest trees af­ter pinyon ips attacks.


other ips species

Pine engraver (ips group) is most problematic in ponderosa and Jeffrey pine, although almost any pine species can be a host. Stress due to drought, fire, or other damage increases a tree’s susceptibly to attack. However, recently cut logs (slash) or wind-thrown trees are preferred. If not properly managed, population levels can build in fresh slash or downed material in the spring. This preferred habitat can create localized outbreaks, killing patches of standing smaller diameter sized trees or topkill on large diameter hosts.

Pine engraver beetle adults are about 1/8- inch long, with anspiney, indented backside. The adults produce they typical Y- or H-shaped galleries. Beetles usually overwinter in the duff layer but may overwinter in previously attacked logs or trees. Once spring temperatures reach 65°F, beetles begin to fly until cold fall weather stops dispersal.

Pondero­sa pine is also a preferred host for several oth­er ips beetles. The Arizona fivespinedips, found in south­ern Utah and the southeast por­tion of Nevada, can be fairly ag­gressive, attack­ing large trees over a wide area when drought conditions devel­op. The emargin­ated ips and six­spinedips, both larger engravers about 1/4-inch long, have caused tree mortality during drought years in eastern Montana. Many other species of ips at­tack pines and spruce. Ips species can be identi­fied by the number and shape of spines on their backsides, and their typical Y- or H-shaped gal­leries containing little frass. Wood borers often infest trees following ips attacks.


Western pine beetle serpentine egg galleries

Typical ips gallery

H-shaped gallery typical of ips 10 Forest Health Protection – Intermountain West & Northern Rocky mountains


This species attacks true firs (less often subalpine fir); Douglas-fir is not a true fir. The insect causes topkill, branch kill and tree mortality, attacking trees >3 inches in diameter. Tree needles generally turn yellow-red within 3-5 months. Evidence of attack be­fore trees fade is of­ten hard to detect; entrance holes are with­out pitch tubes and in the In­termoun­tain West, pitch streamers may or may not be present. Boring dust in bark crevices and around the base of tree or fading needles are more reli­able signs of successful attacks.

Adult beetles are about 1/8-inch long, black, with a truncated, spineless back end. The egg galleries run horizontally across the stem, aver­aging 6 inches in length. Larvae mines radiate vertically out from the egg gallery. Following at­tack, a fungus associated with the beetle stains the surrounding attacked area a yellow-brown color. Larvae overwinter under the outer bark with adult beetles emerging in June. Adult flight may occur from June-September. The life cycle is usually one year.


This species is associ­ated with bark beetle attacks on subalpine fir. Adults are about 1/8 inch long, and brown or black in color. There is a distinctive hairy patch (toupee-like) on the head of the female beetle. The gallery pattern is star shaped.

External evidence of successful attacks by western balsam bark beetle is often diffi­cult to detect. Entrance holes are often high on the trunk, but boring dust may be visible in bark crevices in late summer. Pitch flow may also be observed with fine boring dust present in the pitch if attacks were successful. Needles on successfully attacked trees turn yellowish-red within a year and can remain bright red for several years after death. Outbreaks of this in­sect are often initiated by prolonged drought and windthrow.

Generally a two-year life cycle is observed, but one-year life cycles are also possible. Two peak flights of adult beetles occur, late June/ear­ly July and late July/early August.

Western balsam bark beetle and galleries

fir engraver GALLERies

Challenges of aBark Beetle Outbreak-

Whatare Land Managers Doing?

Federal and State Land Managers

Developing management strategies to miti­gate bark beetle effects is a difficult challenge for Federal and State resource managers. For­est health specialists understand tree and stand characteristics that increase susceptibility for many of the bark beetle species discussed in this brochure and, in conjunction with resource man­agers, develop silvicultural treatments to reduce impacts caused by these insects. Regardless of the treatment bark beetle outbreaks are not pre­ventable; only their impacts can be reduced.

Land management planning is required for all Federal and State administered lands. Public involvement is invited and encouraged as part of the Federal planning efforts. Some areas on Fed­eral lands are excluded or restricted from vege­tation management activities (i.e. wilderness and roadless areas). Resource tools to manage bark beetle populations within these areas are often not available.

Where vegetation management treatments are permitted, Federal and State resource man­agers can develop treatments to reduce stand densities, increase tree species and age diversity, and remove bark beetle-infested trees.

Often resource managers develop treatments to reduce bark beetle impacts within the treated landscapes. Removing infested trees as a stand-alone treatment may help suppress develop­ing populations of bark beetles. But, if adjacent stands contain beetle populations and the treat­ed sites remain susceptible, bark beetles may re-infest the treated area. Protection of individual, high-value trees can be accomplished with in­secticide and pheromone treatments.

Private Landowners

Treatments developed for private lands will vary depending on the objectives of individual owners. Some may choose to do nothing and let nature take its course; others may prefer a more aggressive approach and initiate treatment strat­egies similar to those described for Federal and State land managers.

Land owners who do no treatment and choose to leave infested trees or stands suscep­tible to bark beetles could affect residual trees on adjacent ownerships where treatments have occurred. Mixed ownerships in close proximi­ty to one another with various objectives com­plicate developing effective treatment strate­gies. A number of factors can affect this decision process including: treatment options may not be available to all ownerships, treatment economics may effect implementation and site conditions may be too difficult to treat (eg. steep slopes).

Fortunately, there are effective single-tree treatments available for high-value trees. Repel­lent pheromones and preventative insecticides are treatment options available to private land­owners. These single tree or small area treat­ments will require continuous applications until bark beetle populations collapse. 11 Forest Health Protection – Intermountain West & Northern Rocky mountains


that cause damage similar to that of bark beetles

Other insects or animals can cause damage to trees that may resemble bark beetle activity. We have listed a few of these to help you discern between bark beetle attacks and activity from other agents.


Other insects and diseases can cause dam­age to the needles of trees that may look like bark beetle activity from a distance.

Western spruce budworm (Choristoneuraoccidentalis Freeman) (WSBW) and Douglas-fir tussock moth (DFTM) (Orgyiapseudotsuga­ta (McDunnough)) are two of our most conspic­uous foliage feeding insects. Larvae of both of these moths feed on Douglas-fir, all true firs, and spruce (also larch for western spruce budworm).

Although feeding larvae prefer new nee­dles, older needles are often consumed during outbreaks. Trees often appear reddish-orange in color as partially consumed needles fade. Branch tips will be bare and often covered with silk webbing and dead needles.

Contact your local State forest health spe­cialist for assistance with identification and sup­pression treatments of defoliators.

AmbrosiabeetleS are very small, creat­ing multiple pin holes in wood where they culti­vate a fungi (am­brosia) that they feed on.

Bark beetles have often left their host tree by the time you see red needles. In­spection of the dead tree may reveal in­sects that were not di­rectly respon­sible for the tree’s death.

Most of­ten confused with bark beetles are the metal­lic and long­horn woodborers. Wood borers are much larger than bark beetles. These borers feed on the phloem just as bark beetles do; however, their galleries lack a distinct shape. While developing, the lar­va may drill large oval or round holes into the wood. Depending on the species, their life cycle may take from one to over ten years to complete.

landscape damage

Woodwasp larva make large holes in dead wood similar to wood borers but the larva do not feed in the phloem.

A bark beetle (left) and metalic wood borer (right)

WSBW larvae have paired white spots on both sides of each body segment

Older dftm larva with “tussocks” and “horns”

Even woodpeckers (sapsuckers) can make holes in the bark that may look like bark beetle entrance/exit holes.

Longhorn wood borer

Metallic wood borer

Tree crown damage from feeding larvae

Where to go for help or additional information


■ For on-the-ground technical assistance with insect and forest management on private lands:

- In Idaho, contact Tom ckberg, Idaho Department of ands, (208) 666-8624, techberg@idl.idaho.gov, (http://www.idl.idaho.gov/Bureau/forasst.htm.)

- In Montana, contact Amy Gannon, Montana Department of aturalesources, (406) 542-4283, agannon@mt.gov, (http://dnrc.mt.gov/forestry/assistance/pests/ default.asp)

- In Nevada, contact Gail Durham, Nevada Division of Forestry, (775) 684-2513 or 687-0431, gdurham@forestry.nv.gov, http://forestry.nv.gov/?page_id=241

- In North Dakota, contact Michael Kangas, North Dakota Forest Service, (701) 231-5936, Michael.Kangas@ndsu.nodak.edu, http://www.ndsu.nodak.edu/ forestservice/stateforest/state_forest_home.htm

- In Utah, contact Colleen Keyes, Department of Natural Resources Division of Forestry, ire, and State ands, (801) 538-5211, ColleenKeyes@utah.gov,


- In Wyoming, contact es Koch, Wyoming State orestry Division, (307) 777- 5495, lkoch@state.wy.us, http://slf-web.state.wy.us/forestry/health2.aspx

■ For information on professional pesticide applicators and insecticide registration contact your local state Department of Agriculture, division of pesticide licensing. Web pages to assist you with the contacts are listed below:

- Idaho: http://www.agri.idaho.gov (see noxious weed contacts)

- Montana: http://www.agr.state.mt.us/ (see pesticides, program contacts)

- Nevada: http://agri.nv.gov/index_Plant2.htm or http://agri.nv.gov/PLANT_ Chemistry_Index.htm

- North Dakota: http://www.agdepartment.com/Programs/Plant/Pesticides.html (see laws and regulations for contacts)

- Utah: http://ag.utah.gov/

- Wyoming: http://wyagric.state.wy.us/divisions/techserv/sections/pesticide.htm ■ For general National Forest information, contact the National Forest directly

■ For information on USDA S orest Health Protection for the orthern and Intermountain Region, visit http://www.fs.fed.us/r1-r4/spf/fhp/index.html

■ Visit the FIREWISE™ program at www.firewise.org

■ Additional pictures of the various trees and insects mentioned in this pamphlet can be found at www.bugwood.com


Aield Guide to Diseases and Insect Pests of orthern & Central ocky Mountain Conifers (http://www.fs.fed.us/r1-r4/spf/fhp/field_guide/index.htm)

■ Forest Insect and Disease Management Guide (http://www.fs.fed.us/r1-r4/spf/ fhp/mgt_guide/index.htm)

■ Forest Insect and Disease eaflets (FIDLs) for a variety of forest pests (http:// www.na.fs.fed.us/spfo/pubs/fidl.htm)

■ Using MCH to protect trees and stands from Douglas-fir beetle infestation (http:// www.fs.fed.us/r1-r4/spf/fhp/publications/MCH_brochure/MCH_online.pdf)

■ This pamphlet is also available on-line (http://www.na.fs.fed.us/r1-r4/spf/fhp/ index.htm.html)

The Role

of Fire

Trees with red needles are more flamma­ble than live trees. However, once the needles have fallen, standing dead trees no longer increase wildfire risk. As the trees drop to the ground, the addition of downed woody fuels does increase fire intensity and severity.

Fire is a natural part of the ecosystem. Vegetation in the West has evolved in fire driven ecosystems and in many cases relies on fire for sustainability and forest health.

However, wildfires around human habi­tation are often not desirable. Research in­dicates that the most critical factors to mit­igate fire loss around structures are the construction materials used, and the type and distance of vegetation around the struc­ture.

FIREWISE™ is a multi-agency, non-profit program designed to assist individuals with wildfire survivability to reduce struc­ture losses. The program encourages de­veloping a “defensible space” around your home. Information on how to reduce loss­es to wildfire can be found on a variety of FIREWISE™ websites.

General recommendations to reduce structure losses include:

  1. Roofs should be constructed of non-flammable material.
  2. Enclose places on structures where fire embers can accumulate.
  3. Thin dense vegetation around the home.
  4. Remove brush or dried grasses adjacent to the home.
  5. Landscape with fire resistant plants.
  6. Keep firewood and propane tanks at a safe distance from the home.

Firefighter safety is a primary consider­ation in any fire incident. Creating “defen­sible space” will enhance opportunities for firefighters to safely protect your home.

For additional information on measures to protect your home, visit the FIREWISE™

website (www.firewise.org) or

contact your local fire department.

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual’s income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille large print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office Of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410, or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer.

The use of trade or firm names in this publication

is for reader information and does not imply

endorsement by the U.S. Department of Agriculture

of any product or service.

06/09 12 Forest Health Protection – Intermountain West & Northern Rocky mountains

Printable version of Douglas Fir Tussock Moth (PDF)

Douglas-fir Tussock Moths

5.542 Fact Sheet No. Insect Series|Trees and Shrubs

by W. Cranshaw, I. Aguayo, and D. Leatherman*

Caterpillars of the Douglas-fir tussock moth, Orgyiapseudotsugata(McDunnough), chew the needles of spruces, Douglas fir and true firs. During outbreaks they may cause extensive defoliation, with injury typically first concentrated at the top of the tree. Older caterpillars may rapidly defoliate a tree and tops may be killed, sometimes after only a single season of severe injury. Following repeated attacks over several seasons whole trees may die or be weakened to the point of inviting fatal attacks by bark beetles.

Problems in urban forests along the Colorado Front Range primarily involve blue spruce. Historically, outbreaks in our native forests have involved Douglas fir and been infrequent, although lately, probably due to the accumulated effects of fire suppression practices, these have occurred more often. The insect is much more important as a forest pest in the northwestern United States.

Douglas-fir tussock moth caterpillars also can cause problems because the larval hairs can be irritating and are capable of producing a painful rash. Individual reactions to the hairs are highly variable with some people reacting strongly following exposure while others have little reaction.


Young tussock moth caterpillars are blackish with long body hairs, producing brightly colored tufts of hair as they grow larger. A mature larva is 1.2-1.4 inches long, with a gray to brown body and shiny black head. Two long tufts of black hairs project forward from the head, and a similar tuft projects backward from the rear of the body. Dense, light brown patches of hairs and red spots occur on the first four and the last abdominal segment and there is an orange stripe on each side.

The cocoon surrounding the pupal stage is brownish gray and covered with hairs from the body of the larva. Cocoons usually are attached to foliage but may be found on tree trunks, rock, or other objects in the vicinity of a previously infested tree.

The adult males are moths with rusty-colored forewings and gray-brown hind wings, with a wing-span of about one inch. Females are thick-bodied and wingless, found in close association with the spot where they earlier pupated.

The egg mass, laid on the pupal cocoon of the female, contains about 300 white spherical eggs laid in several layers. The entire mass is covered with a frothy substance that is intermixed with body hairs of the mother. Movement of Douglas-fir tussock moth into new locations around the state sometimes result from humans incidentally moving construction materials or other items that have attached egg masses.

Life History and Habits

Douglas-fir tussock moth spends the winter as an egg within the egg mass. Eggs hatch in the spring, often in late May, typically following bud break. The small, hairy caterpillars migrate, moving to the new growth but also often dispersing upwards in the trees. This latter habit allows some of the caterpillars to be disperse by winds, which will carry the small, hairy caterpillars. Since the adult female moths do not fly, wind-blown movement of young larvae is an important means of initiating new infestations.

The caterpillars first feed solely on the newer foliage, and partially eaten needles may wilt and turn brown. Later, the older caterpillars will move to older needles as

Quick Facts

  • Douglas-fir tussock moth caterpillars feed on needles of spruces, Douglas-fir and true firs.
  • Sporadically outbreaks of Douglas-fir tussock moth occur in several Front Range communities. Less commonly it occurs as a forest pest in Colorado.
  • Numerous natural enemies attack Douglas-fir tussock moth and these will often control outbreaks after a season or two.
  • Several insecticides can be used to control Douglas-fir tussock moth during outbreaks.

©Colorado State University Extension. 3/95. Revised 2/09.


*The original version of this publication was produced by R.E. Stevens of the Rocky Mountain Forest and Range Experiment Station, D.A. Leatherman, entomologist with Colorado State Forest Service and J.W. Brewer with the former department of zoology and entomology of Colorado State University. 3/95. Revised by W. Cranshaw, entomologist, Extension, Colorado State University, I. Aguayo and D. Leatherman, current and former entomologists, Colorado State Forest Service. 2/2009

the more tender needles are eaten. During feeding, particularly when disturbed, larvae may drop from branch to branch on long silken strands. By mid-July or August, the larvae become full grown and many may migrate away from the infested tree. They pupate in brownish spindle-shaped cocoons in the vicinity of the infested trees.

In forests another defoliating insect, the western spruce budworm, favors the same hosts as Douglas-fir tussock moth and often occurs coincidently with it. As these two develop on slightly different schedules – tussock moth egg hatch usually lags behind the initiation of budworm larval feeding in the spring by as much as three weeks – care should be taken to properly identify the two and determine which is the more damaging. This becomes particularly important if controlling actions are taken. Applying insecticides for one species at the ideal timing of the other may result in effective treatments for both.

The adults emerge from late July through mid-August. The males are winged and are strong fliers, but the females have only minute, non-functional wings. Mating occurs in the immediate vicinity of the female pupal case and they then lay their characteristic mass of eggs covered with grayish hairs. There is one generation produced per year.

Management in Landscape Plantings

Outbreaks of Douglas-fir tussock moth are cyclical due to effects of several natural controls. At least seven species of parasitic wasps and a tachinid fly have been identified as parasites that are locally present. Caterpillars may be killed by general predators, notably spiders. A nuclear polyhedrosis virus disease, known as the “wilt disease”, also can be an important mortality agent during outbreaks. Bird predation on tussock moth caterpillars is considerable during the early larval stages but the longer, dense hairs on larger caterpillars makes predation by most bird species difficult. In addition, severe weather, particularly following egg hatch, can be important in limiting Douglas-fir tussock moth populations. The cumulative effects of these natural controls rarely allow Douglas-fir outbreaks to persist more than a couple of years before reverting to a normal non-damaging population level.

Surveying the site for the presence of egg masses in winter and early spring provides an outbreak potential estimate. When egg masses are easily found in the vicinity of known host trees, a higher risk exists for subsequent injury. However, trees should be monitored shortly after bud break to confirm the presence of a potentially damaging population.

Chemical controls can be effective but need to be applied thoroughly to the top of the tree. In addition, younger larvae are much more effectively controlled than older larvae, so treatment timing is best shortly after eggs have hatched. In landscape plantings, pyrethroids such as permethrin (Astro), cyfluthrin (Tempo), bifenthrin (Talstar, Onyx) and lambda-cyhalothrin (Scimitar) are effective against Douglas-fir tussock moth caterpillars. Carbaryl (Sevin, Sevimol), teburenozide (Confirm, Mimic) and spinosad (Conserve) are alternative treatments that can provide good control.

In forest settings considerations surrounding treatments and insecticide

Figure 1: Adult males of the Douglas-fir tussock moth.

Figure 2: Tussock moth egg mass at egg hatch.

Figure 5: Top-down defoliation pattern typical of Douglas-fir tussock moth.

Figure 3: Douglas-fir tussock moth larvae.

Figure 6: Douglas-fir tussock moth larvae with a disease, nucleo-polihydrosis virus.

Figure 4: Douglas-fir tussock moth larval damage.

options differ. Applications are typically made by air so large areas are simultaneously sprayed with insecticide. As a result, the potential for contamination of fish-bearing surface waters exists. Also, the presence of endangered species, such as the Pawnee Skipper, becomes particularly important to decision making. Where Douglas-fir tussock moth outbreaks are sufficiently threatening to warrant treatment, insecticide options include the microbial insecticide Bacillus thuringiensis (Foray, Dipel) and the insect growth regulators diflubenzuron (Dimilin) or tebufenozide (Confirm, Mimic).

This fact sheet was produced in cooperation with the Colorado State Forest Service.

Colorado State University, U.S. Department of Agriculture and Colorado counties cooperating. CSU Extension programs are available to all without discrimination. No endorsement of products mentioned is intended nor is criticism implied of products not mentioned.

Printable version of How to Identify a Hobo Spider (PDF)

How to identify (or misidentify) the hobo spider

Rick Vetter 1 and Art Antonelli 2 PLS 116 Page 1

Since the late 1980s, many people in Washington have been concerned about the hobo spider because it has been blamed as the cause of dermatologic wounds. We offer here a guide to help identify some medium-sized Washington spiders found in homes. However, keep in mind that without a microscope you may not be able to identify hobo spiders and may have to settle for determining that your spider is NOT a hobo spider. This may be frustrating and not the goal you had in mind, however, quite often the question is not "What spider do I have?" but "Do I have a hobo spider?" You should be able to learn enough to eliminate many spiders from consideration without a microscope and sometimes with just the naked eye. Most people want a world with simple black/white answers but you must realize that there many shades of gray in between and this is the reality of spider identification.

This publication was initiated because there is no currently available guide to spider identification for the person with limited arachnological skills. Most of the previous guides for hobo spider identification try to give a simplistic way to discern hobo spiders. We have found that many well-intentioned people misconstrue the information and confidently misidentify their non-hobo spider as a hobo. The other references actually are reliable if you already know something about spider identification similar to the fact that a dictionary is a book that helps you spell words if you already know how to spell words. However, the misidentification of harmless spiders as hobo spiders can result in inappropriate anxiety and/or the unnecessary spraying of insecticides to kill off spider populations which are actually beneficial species

because of the insects they eat. What this publication tries to do is

1 Dept. Entomology, Univ. Calif. Riverside, CA 92521

2 Extension Specialist, Wash. St. Univ., Puyallup, WA 98371

show you that the answers are not easy to obtain but if you are interested in taking your discriminatory skills up a notch, with a little practice, you should be able to confidently determine the characteristics of spiders that are NOT hobo spiders, which will be the majority of the medium-sized spiders you will encounter.

Fig. 1 Hobo spider

Photo by P. K. Visscher © PLS 116 Page 2

A general warning

Most non-arachnologists try to use coloration as a diagnostic identifying feature. This is one of the least reliable characteristics for identification of hobo spiders because of the great variation amongst specimens within a species and because similar species sometimes overlap in their appearance with hobos. If you try to identify them by size, you will also be mistaken because the variation is tremendous. Many other species look the same to the non-arachnologist who lumps them all together as hobo spiders and often is wrong. If you continue to try to determine spiders with coloration or size, then this publication is not going to help you. You must be willing to take your skills above the level of the non-arachnologist, learn a few anatomical structures and then you will have better success. As an analogy from the world of ornithology, it is easy to determine an eagle from an owl, etc. but it takes much more skill and effort to differentiate amongst the many species of similar-looking warblers. Thus, it is the same for the hobo spider and many of the medium-sized Washington spiders. You will need to be more discriminating when dealing with hobo spiders because identification is not easy. This guide is geared toward the interested reader who has a magnifying lens or hand lens, similar to what Master Gardeners or entomologists would use. Yet even with a lens, quite often you may be able to determine that your spider is NOT a hobo spider and nothing more.

For the few who have access to microscopes we present information on how to definitively identify hobo spiders to species. For the advanced beginner, this can only be reliably achieved by comparing the male and female reproductive structures to the pictures presented here. If you are able to do this, you can learn the skills of an amateur arachnologist and can determine without a doubt whether or not you are in possession of a hobo spider.

We present mostly identification information here. If you wish to learn the biology or other aspects, you should check out the references at the end of the article.

A little bit about the spiders

The hobo spider is found throughout Washington and makes a funnel web which is a trampoline-like flat sheet leading back into a hole between bricks, under wood or in shrubs. However, there are many closely related species of spiders which also make similar webs so just because you see funnel webs on your property, does not mean that there are hobo spiders in those webs.

The scientific name of the hobo spider is Tegenariaagrestis. Also living in Washington are 2 other closely related spiders, the giant house spider, Tegenariaduellica (known as Tegenaria gigantea to some) and the barn funnel weaving spider, Tegenariadomestica (also known as the domestic house spider to some). All three of these spiders originated in Europe. Related spiders (Agelenopsispotteri, Agelenopsispennsylvanica and Hololenanedra ) are often misidentified as hobo spiders. All of these are common Washington spiders which are brown, make funnel webs and belong to the family Agelenidae. PLS 116 Page 


You will need to know some important diagnostic anatomical features (Figs. 2, 3) in order to be more discriminating with spider identification.

Cephalothorax - the first main body part to which the legs are attached

Abdomen - the second main body part

Palp - the male reproductive structure. This is a swelling or knob on the end of the "feelers" in front of the body. Some people have described it as looking like a pair of boxing gloves.

Sternum - on the underside of the cephalothorax. A flat, shield-like surface surrounded by the legs

Epigynum - the female reproductive structure, a hardened, darkened structure on the underside of the abdomen closer to the cephalothorax than the middle of the abdomen. Immatures and male spiders have nothing in this area.

Fig. 2 male black widow spider

Photo by D. Boe ©

Fig. 3 left - giant house spider

right - hobo spider

Photo by R. Vetter ©

If you have a hand lens…. - what is NOT a hobo spider

If the only magnifying device you have is a hand lens, you may have to be satisfied with knowing what is not a hobo spider. Try this out and very soon, you will be able to hone your skills and possibly move up to the next level of identification such that hobo spiders will be very easy to identify. PLS 116 Page 4

1- Spots on the sternum? Not a hobo

If your spider has 3 or 4 pairs of light spots on the lateral portions of the sternum (Fig. 4), THEN IT IS NOT A HOBO SPIDER. These spiders are the other two Tegenaria species, the giant house and the barn funnel weaving spiders. Hobo spiders have a light stripe running down the middle of the sternum. So the rule here is, "If you see spots, then a hobo it's not". However, be aware that in some specimens of the giant house and barn funnel weaving spiders, the spots are very, very faint and hence look very similar to a hobo spider

Fig. 4 left - giant house spider right - hobo spider

Photo by R. Vetter

This is why we emphasize that you can't use coloration alone to accurately identify a hobo spider.

The giant house spider is more common than the hobo spider in the Pacific area west of the Cascade Mountains. These spiders are usually much larger than hobo spiders (and people assume bigger spiders are more dangerous). In western Washington cities, they typically outnumber hobo spiders about 3 to 1 so therefore, you are much more likely to encounter a giant house spider than a hobo spider. There are no populations of giant house spiders east of the Cascades in Washington so a spider with a spotted sternum is probably the smaller barn funnel weaving spider.

2- Distinct stripes on the cephalothorax? Not a hobo

If your spider has two very distinct longitudinal dark stripes on the top side of the cephalothorax (Fig. 5), THEN IT IS NOT A HOBO SPIDER. Hobo spiders have indistinct or diffuse patterns. Washington spiders with distinct dark stripes are either Agelenopsis or Hololena spiders and possibly some wolf spiders. Unfortunately, these spiders do not have common names

Fig. 5 Hololenaspecies spider

Photo by D. Boe ©

3- Dark rings around the legs? Not a hobo

If you can see dark rings around the legs of your spider (Fig. 5), THEN IT IS NOT A HOBO SPIDER. Hobo spiders have uniformly colored legs. The most PLS 116 Page 5

common spiders that have rings around their legs are the barn funnel weaving spider and some of the other agelenid spiders like Hololena.

4- Legs and cephalothorax are shiny and dark-orange in color? Not a hobo.

If your spider has legs that are shiny and lacking fine hairs, THEN IT IS NOT A HOBO SPIDER. If the cephalothorax is also shiny and dark-orange to a mahogany in color, this is probably a Callobius spider (Fig. 6). There are many species of Callobius spiders in Washington however, Callobiusseverus is one of the most common and most widespread in Washington's most heavily populated areas. This spider is very often submitted as a potential hobo spider because of the pattern on the abdomen. Also in the side view, the palp of Callobius males has large, conspicuous, pointed projections (Fig. 7). Hobo spiders have one very small flat-top projection (see Fig. 9). The palp of the male Callobius spider is not the one from the Pacific Northwest but it will look similar enough to it such that you will be able to recognize it.

Fig. 6 Callobiusspider Fig. 7 Male Callobiuspalp projections

Photo by David Phillips © (top of palp is cut off in the picture)

www.riverfriends.com Photo by R. Vetter ©

5- The palp of the male is long and pointy? Not a hobo.

If the extreme fleshy tip of the male palp is long, thin and finger-like, THEN IT IS NOT A HOBO SPIDER. If you look at Figures 8 & 9, two of the three male palps of the closely-related Tegenaria species have long, pointed, finger-like tips. The tip of the hobo spider is more blunt.

So how do you tell for sure that you have a hobo spider?

Unfortunately, the answer is that unless you are able to examine the very small reproductive structures, you are cannot definitively identify a hobo spider. But if you have progressed this far in your arachnological skills, you will realize that you PLS 116 Page 6

have eliminated many spiders from consideration as hobo spiders which may be sufficient for your needs.

The only sure way to identify a spider as a hobo spider is to compare its reproductive structures that define it as a species. You will probably need a microscope to examine these structures.


1- FORCEPS: You should have two pairs of forceps for manipulating spiders, moving legs out of the way, etc. The finer the tips the better. BioQuip in southern California has everything entomological. They have inexpensive fine forceps for about $2.50 but if you wish to get the professional models, watchmaker's forceps are the best. They cost about $15 a pair and are also available from BioQuip and probably from various other sources like electronics stores, medical supply places, etc.

2- ILLUMINATION - you should have a strong illumination source, preferably from the side that will give better contrast of the features. Straight-on lighting will make the subject look flat. Example, photographs of hills and mountains show much more detail of the topography at dawn and dusk because they accentuate the differences in contours. The same goes for microscopic spider work. If you don't have a scientific illuminator, a high-intensity flashlight should be sufficient. If you are having trouble seeing some of the structures, move the illumination source around. This will give you different perspectives of the contours of the features.

3- SUBMERGE THE SPIDER IN ALCOHOL: to properly identify spiders, the spider needs to be completely submerged in alcohol. The reason for this is that the hairs of the body will cloak important features or distort the light. If the spider is completely submerged in alcohol, you will be looking at fewer reflections off the body parts.

4- ALCOHOL: If you are at a scientific institution, you should have no trouble getting ethanol which should be diluted to 70% with water. The general public can obtain denatured alcohol (purposely contaminated with compounds like acetone (i.e., nail polish remover) so that it is not potable). Rubbing alcohol (isopropyl alcohol) is 70% right off the drugstore shelf but causes specimens to become brittle and there are some health risks for humans more so than ethanol.

5- OBSERVING SPIDERS ALIVE: if you don't want to kill the spider, you can place the spider in a clear plastic bag and then gently flatten the bag against a contrasting surface. The spider will then be immobilized with its legs out flat and with practice, you should be able to see many of the features mentioned here. After that, you can just release the spider to the garden so it can eat more insects.

PLS 116 Page 7

Male palps

The best way to examine the male reproductive structures is to remove them from the spider because the legs often get in the way, the palp usually curls downward making it otherwise difficult to identify. Once you remove the palp, place it such that you can see all the surface structures. By convention, arachnologists always remove the left palp from a mature male spider. (Be aware that the palps of immature male spiders are merely swollen bulbs with no structures on it. They have one more molt to maturity. If this is what you have, species identification is virtually impossible and you might as well throw it away.)

In this publication, we will only address the different palps of the three Tegenaria species because by the time you have gotten this far, you should have eliminated the other spiders as non-hobos. Actually by this time you should have been able to eliminate most of the normal-looking giant house and barn funnel weaving spiders too. Again, because of variation in color and size, several specimens have fooled experts until the reproductive structures were examined.

Fig. 8 Left male palps showing differences in the surface features

Left - hobo spider, center - giant house spider, right - barn funnel weaving spider

Photo by R. Vetter ©

With the left male palp lying "on its back", you should see a variety of complex structures. Although this may appear difficult, as you look more closely, you will see darkened prominences arising from the palp. In the hobo spider, there is a hardened structure that wraps around on the outside of the palp, curves toward the middle and has two little prongs on the end. In the giant house spider, there is a thick prong, which points downward away from the palp. In the barn funnel PLS 116 Page 8

weaving spider, there is a short prong near the top which just pokes toward the outside. If you can identify the palp to any of the pictures here, then you have performed the task of a qualified arachnologist and have definitively identified the spider to species.

Fig. 9 Side view of left male palps showing differences in the RTAs

left - hobo spider, center - giant house spider, right - barn funnel weaving spider

Photo by R. Vetter ©

In a side view, there is a structure on the tibia called the retrolateral tibial apophysis (RTA). In the hobo spider, the RTA (Fig. 9) is a single projection that is squared off on top. In the giant house spider, the RTA has two projections, each on the end of a saddle. In the barn funnel weaving spider, there is a single projection that is pointed on top. We realize that the structures on the male palp may be difficult to discern here despite slight digital-enhancement. However, after comparing these pictures to actual palps under a microscope, you should readily become more proficient at determine hobo spiders. These images should give you an idea of some characters such that you can eliminate some spiders from consideration.

Also in the figure above, for the giant house spider you can see the longer fingerlike, upward extension and also the downward projecting prong on the surface of the palp. The size differences between spiders can also be detected.PLS 116 Page 9

Female Epigynum

The epigynum of the female is the opening to her reproductive organs and is usually a hardened plate. It is located on the underside of the abdomen. This is going to be more difficult than the male and you will surely need a microscope for this whereas with the male palp, sometimes a very good hand lens will suffice. In immature females, there is nothing near the location where the epigynum will eventually form and you might as well throw away the specimen.

In the hobo spider, the epigynum contains a large atrium (cavity), in the middle, which is surrounded by thick, raised ridges (in Fig. 10, two slanted white side ridges and one below). If you can see an epigynum similar to the figure to the right, then you have a hobo spider because nothing else looks like this. Be aware that other spider species have an atrium but it looks very different.

Female giant house spiders (Fig. 11) have no atrium (the middle portion is a shiny, flat surface) and have large pointed spurs near the bottom of the epigynum that point toward each other. You may need to remove the hairs from this area with a needle to see the spurs.

The barn funnel weaving spider (Fig. 12) is sometimes very difficult to identify because the variation in the epigynum sometimes leaves a very subtle structure. However, the barn funnel weaving spider female epigynum does not have an atrium and looks something like a bracket with a blurry spot on either end.

Fig. 10 hobo spider epigynum

Photo by R. Vetter ©

Fig. 11 giant house spider epigynum

Photo by R. Vetter ©

Fig. 12 barn funnel weaving spider epigynum

Photo by R. Vetter © PLS 116 Page 10

References providing biology and distribution information:

Akre, R. D., and E. A. Myhre. 1991. Biology and medical importance of the aggressive house spider, Tegenariaagrestis, in the Pacific Northwest (Arachnida: Araneae: Agelenidae). Melanderia 47: 1-30.

Baird, C. R., and R. D. Akre. 1993. Range extension of the aggressive house spider Tegenariaagrestis into southern Idaho, Utah and Montana. Proc. Wash. St. Entomol. Soc. 55: 996-1000.

Crawford, R., and D. K. Vest. 1989. The hobo spider and other European house spiders. Burke Mus. Educ. Bull. #1, 4pp.

Vetter, R. S. 2001. Hobo spider. Univ. Calif. Pest Notes #7488, 3 pp. (http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7488.html)

Vetter, R. S., A. H. Roe, R. G. Bennett, C. R. Baird, L. A. Royce, W. T. Lanier, A. L. Antonelli and P.E. Cushing. (submitted). Distribution of the medically-implicated hobo spider (Araneae: Agelenidae) and its harmless congener, Tegenariaduellica in the United States and Canada. (J. med. Entomol. - in press.)

Printable version of Managing Mountain Pine Beetle (PDF)

Managing Mountain Pine Beetle (MPB) Attacking Urban And Shelterbelt Trees In Montana

1) Learn to recognize the signs and symptoms of MPB attack. Evaluate the degree of risk to pine trees on your

property. Is the property close to an infested forest? Are there infested trees on your property or in the general


2) Practice prevention. Remove and destroy infested trees by June 1 before beetles emerge to attack nearby

trees. Do not bring infested firewood onto your property. If the pine trees are at risk of attack keep them well


3) If your pine trees are at risk, consider protecting them. Trees can be protected by spraying the trunks with an

insecticide or by applying a repellent pheromone prior to July 1.

4) During the fall season evaluate MPB damage to your pine trees and develop a management plan that utilizes

prevention and protection if necessary. The current infestation in Montana will likely last for at least another 3

to 5 more years.

Signs And Symptoms Of Mountain Pine Beetle Attack

In Montana beetles typically fly during July and August when they attack pine trees. All species of pine can be

attacked, but native lodgepole and ponderosa pine, and introduced ornamental Scots pine are preferred hosts.

Hundreds of the tiny beetles bore through the tree bark and lay eggs within the inner bark. The white grub-like

larvae feed on the inside of the bark. Pitch tubes produced at beetle entry points, and boring dust that

accumulates at the base of the tree, are some of the first signs of attack that become visible in August and


Figure 2 above: Scots pine tree mass attacked by thousands of beetles. At each entry point the tree exudes sap

and pitch in an attempt to repel the beetle, producing distinctive “pitch tubes”. Each pitch tube represents a

point of entry where a single beetle chewed trough the bark.

Figure 3 above: Trees may not always produce pitch tubes, particularly drought stressed trees that have less

sap. Boring dust at the base of the tree is another sign of infestation. As the adult beetles chew and construct

galleries underneath the bark they push out the dust. With hundreds of beetles at work, boring dust accumulates

at the base of the tree, looking something like sawdust. Boring dust is a sign of an active infestation.

Figure 4 above: Left, after boring through the bark, female beetles construct a vertical gallery underneath the

bark. When a tree is attacked by hundreds of beetles, the inner bark is destroyed by their feeding activity

(middle picture). After mating, female beetles lay eggs along the vertical gallery. The eggs hatch into small

grub-like larvae (upper right) that feed in a horizontal direction. The smaller larval feeding galleries radiating

out from the larger vertical gallery produced by the adults produces a characteristic pattern underneath the bark

(lower right hand corner).

Figure 5 above.

As mountain pine beetles bore into a tree, they bring with them blue stain fungi that colonize the tree. The blue

stain commonly seen on pinewood lumber or furniture is caused by blue stain fungi. The fungi invade the inner

bark as well as the sapwood of the tree trunk The picture above left is a cross section of pine tree with blue stain

fungi growing towards the center. It is the combined action of the beetle feeding and the stain fungi that girdles

and kills the tree. Although mass attacked trees will stay green over the winter (center picture) much like a

Christmas tree, the damage has been done. The tree is girdled, and when temperatures rise in the spring, mass

attacked trees will begin to turn yellow and die from lack of water and nutrients (right-side picture). Despite the

snow on the ground, the picture above right was taken during April 2009.

Will My Urban Pine Tree Die?

In some cases pine trees can successfully repel beetle attacks, particularly if the tree was attacked by a smaller

number of beetles, such as a “strip attack”. A strip attack occurs when only one side of the tree is attacked. In a

forest setting, sacrificing a few trees for the benefit of the forest is acceptable. However, in an urban setting,

homeowners and landowners do not want to cut down high value trees unless they are sure that they will die.

Because some trees may remain green well into the spring before they die, it is not as simple as waiting for

them to turn red. Predicting the fate of “strip attacked” trees is variable and difficult. First, the trees health can

be monitored into the spring season. If attacked trees turns yellow during April and May they will not survive.

Second. small 1” square pieces of bark can be cut from the trunk of attacked trees on the North, East, South and

West sides. If the inner bark on three or more squares is damaged, the tree will most likely NOT survive. If two

or more squares have healthy bark, tree has a CHANCE of surviving. These trees may benefit from extra

watering in the spring. Healthy bark is white and moist, damaged bark is brown and “chewed up”, see Figure 4

above. However, if infested trees are not removed and destroyed by July 1, they present a risk to neighboring

healthy pine trees (see prevention section below).

Is My Spruce Tree At Risk?

Pine trees are the preferred host of the mountain pine beetle and spruce are at low risk. Occasionally other

conifer species such as spruce and fir can be attacked. In a forest this typically occurs when beetle populations

are high and there are no other hosts available (all of the pine trees have been killed during the infestation). In

urban environments spruce trees right beside a mass attacked pine tree have been attacked. These cases are

likely “spill over” attacks, when too many beetles are attracted to the primary host and the beetles go to the next

closest conifer. In the city of Great Falls approximately 1000 attacked trees were identified and only about 6-8

were spruce trees less than 1% of the attacked trees were spruce. Overall the risk is low, but occasionally it

can occur. Also be aware that different species of bark beetles can attack spruce and fir, such as the spruce and

Douglas fir beetles.

Figure 6: Adult mountain pine beetles under the bark of a Scots pine tree. These are tiny beetles not much

larger than a grain of rice.


If your trees are at risk of attack, consider preventative measures. Well watered trees are able to produce more

sap and may “pitch out” and repel the beetles, and are generally more able to recover from attacks. If you have

infested trees on your property consider removing and destroying them prior to June 1. During July and August

a new generation of beetles emerges from infested trees to look for new hosts to attack. Healthy pine trees that

are close to infested trees are at much higher risk of attack. When infested trees are removed, the beetles

underneath the bark must be destroyed by chipping, burning or burying the wood. Simply cutting and splitting

the wood does not kill the beetles underneath the bark. Contact your local county agent or city forester to learn

if your area has a designated disposal site.

Figure 7: Mountain pine beetle life cycle.

Scientific Name: Dendroctonusponderosae.

Hosts: Primarily lodgepole and ponderosa pines,

but any pine species can be attacked. Introduced

ornamental Scots pine is highly attractive to the


Most of its life cycle is spent underneath the tree

bark where it typically takes one year to develop

through egg, larva, pupa and adult stages.

Adult beetles fly during July and August attacking

pine trees. Eggs hatch and larvae feed during the

fall season. Immature larvae spend the winter

underneath the bark. The following spring season

larvae resume feeding and develop into pupae on

the way to becoming the next generation of adult

beetles that emerge during July and August.


Care should be taken when firewood is cut and transported. The beetles can continue to develop under the bark

of infested firewood and emerge to attack nearby pine trees. Standing dead pine trees that are completely greybrown

typically do not have living bark beetles. Trees attacked during the fall season harbor beetles until the

end of August of the following year. Pine trees that are red during July and August may contain beetles. Trees

cut for firewood can be inspected by removing some bark with an axe. Sign of old abandoned galleries is fine

as long as there are no adult or larval beetles present (Figures 1 and 4).


Prevention is helpful but alone it may not be enough. High value urban pine trees can be protected from attack

using a repellent pheromone (verbenone) or by spraying the tree trunks with an insecticide.


Mountain pine beetles produce attractive and repellent pheromone chemicals when attacking pine trees. The

first beetles to attack produce an aggregation pheromone that attracts other beetles in the area to “mass attack”

and overcome the host tree’s defenses. When the tree is full the beetles begin producing an anti-aggregation

pheromone that prevents too many beetles from attacking the same tree. The anti-aggregation pheromone,

called verbenone, is sold commercially. Verbenone is sold as a liquid pouch that is attached to the tree trunk, as

the verbenone evaporates beetles in the area can smell it and they are repelled.

Two verbenone pouches should be attached to each high value pine tree, on the north facing side of the tree

trunk about six feet high. The pouches should not be placed on top of each other, they should be spaced a few

inches apart, one on the northeast side and one on the northwest side. The north side of the tree is cooler and

prevents rapid evaporation of the pheromone. Commercial packaging may provide instructions for different

regions in North America. In Montana MPB typically flies during July and August.

For best effectiveness verbenone pouches should be applied at the end of June, before July 1.

Figure 8: The repellent pheromone verbenone is sold as liquid pouches

that are attached to the tree trunk. In forests vebenone is spaced and

applied in a grid pattern. In urban settings, high value pine trees are

protected by applying two pouches per tree at the end of June, before the

first of July.

USDA Forest service research has found that two pouches of verbenone applied to each pine tree at the end of

June protected 80% or more of the trees that were treated (see “verbenone report” link). Please note that these

recommendations are for protecting small numbers of high value trees. Recommendations for deploying

verbenone in forest and woodlot settings are based on numbers of pouches per acre of forest, please refer to the

DNRC Forestry Division website (http://dnrc.mt.gov/forestry/Assistance/Pests/mtnpinebeetle.asp).

Verbenone is now sold at retail stores in


Verbenone is available at retail stores in Montana or directly through two companies in Vancouver British


Phero Tech, Inc. Synergy Semiochemical Corp.

7572 Progress Way Box 50008, South Slope RPO

Delta, B. C. Canada V4G 1E9 Burnaby, B. C. Canada V5J 5G3

Phone: 604-940-9944 Phone: 604-454-1121

http://www.pherotech.com http://www.semiochemical.com


Verbenone is non toxic and only affects the mountain pine beetle. It is easy to apply. However, it is not as

effective as insecticides sprayed onto the tree trunk. Tree trunks need to be covered thoroughly on all sides,

from ground level up to a stem diameter of about 4-5 inches. Trees can be treated from April through to the end

of June. Several insecticides are available for controlling MPB: SevinXLR (agricultural/forest use), SevinSL

(urban use), Astro and Onyx. All are 95-100% effective in protecting pine trees from MPB attack during the

same year of application. Sevin can provide two years of protection, the year of application and the following

year. Protection during the second year may be more variable, but applying Sevin once every two years may be

more cost effective particularly for larger numbers of trees.

Trees must be sprayed protectively, before the beetles fly and attack. Spraying trees after they have been

attacked will not save them. Beetles come into contact with and ingest the insecticide when boring through the

bark. Previous studies have found that systemic insecticides are not effective against bark beetles. Registered

pesticide applicators are recommended; when using an insecticide carefully follow the label instructions.


Is some sort of action necessary? This is not an easy question, it relates to the degree of risk and the potential

consequence. In urban environments it is difficult to predict where the beetles may turn up. However, after the

beetles have mass attacked a tree, the damage has been done and there are no reliable treatments to save it. The

decision is really a balance between the risk that your trees will be attacked and killed and the cost of taking

action to protect them without ever knowing whether they will be attacked.

Risk: How did the beetles find their way from forests to isolated shelter belts in 2008? Beetles can fly

considerable distances, but they may also be aided by prevailing winds. Future occurrences in urban

environments are difficult to predict. We do know that the mountain pine beetle infestation will continue for

several more years in the surrounding pine forests. If your or your neighbor’s trees were attacked in 2008, it is

reasonable to think that the trees are at risk again during the summer of 2009. Mountain pine beetles live in

forests, the closer your location is to an infested forest, particularly if it is downwind, the greater the risk.

Printable version of Montana Bee Identification Guide (PDF)

Montana Bee Identification Guide

  • Solitary; nest in natural or man-made holes such as beetle tunnels or wood nesting blocks.
  • Females cut circular pieces from leaves and use them to line their nests.

Casey M. Delphia1, Kevin M. O’Neill1, and Scott Prajzner2

1Department of Land Resources & Environmental Sciences, Montana State University, Bozeman, MT

2Department of Entomology, Ohio State University OARDC, Wooster, OH

In cooperation with Pollinator Partnership

Bee Identification

Bees, like other insects, have three body segments: a head, thorax, and abdomen. The headconsists of the compound eyes, antennae that are segmented and bent, and mouthparts that include jaws for chewing and a tongue for drinking nectar. The thoraxbears the legs and four wings (two forewings and two hind-wings). The abdomencontains the sting in female bees. Female bees also have special pollen-carrying hairsor other structures commonly found on the hind legs or the underside of the abdomen. For example, honey bees carry pollen in a pollen basket which is an area on the hind leg that is bare and surrounded by incurving hairs.

Honey bee (Apis mellifera)

Bumble bees (Bombusspp.)

Family: Apidae. Heart-shaped head; hairy eyes; black to amber-brown body with pale and dark stripes on abdomen; barrel-shaped abdomen; pollen basket on hind legs; 10-15mm.

Family: Apidae. Robust, hairy bees; black body covered with black, yellow, orange, or white hairs in bands; pollen basket on hind legs; 10-23 mm.

©2010 Lynette Schimming

  • Social colonies; live in man-made hives and natural cavities like tree holes; swarm to locate new nests.
  • Honey bees are managed for crop pollination and honey production.

Leafcutting bees (Megachilespp.)

Family: Megachilidae. Head as broad as thorax; large jaws used to cut leaves; black body with pale hair bands on abdomen; pollen-carrying hairs on the underside of abdomen; 7-15 mm.©2008 RKD Peterson©2007 RKD Peterson

©2005 Hartmut WischSweat bees (Family: Halictidae)Many forms including: dull black/brown body with light abdominal hair bands, bright metallic green, dull metallic blue, copper, or green, and black with a red abdomen (parasites of other bees); pollen-carrying hairs on hind legs (except in parasitic bees); 3-11mm.

©2010 Lynette Schimming

© 2009 Gary McDonald

  • Solitary, communal, and semisocialsoil nesters; some are attracted to the salt in your sweat. 

© 2009 Gary McDonald

© 2010 Tom Murray

©2011 Casey M Delphia

Bees play an important role in natural and agricultural systems as pollinators of flowering plants that provide food, fiber, animal forage, and ecological services like soil and water conservation. In fact, approximately three-quarters of all flowering plants rely on pollinators to reproduce. In addition to honey bees, native bees provide valuable pollination services. Though unknown, the number of native bee species in Montana is likely in the hundreds.

This guide provides information for identifying 10 types of bees commonly found in Montana including descriptions of key characters, size (mm), nesting habitat, and other identifying behaviors.

©2011 Casey M Delphiaabdomen


headpollen-carrying hairs on abdomenpollen-carrying hairs on hind leg

  • Social colonies; often nest underground in small cavities like old rodent burrows.
  • Bumble bees can buzz-pollinate, which is important for plants that require vibration to release pollen.

©2009 Casey M Delphia

Mason bees (Osmiaspp.)

Yellow-faced or masked bees (Hylaeus spp.)

Small carpenter bees (Ceratinaspp.)Family: Apidae. Shiny, dark metallic blue-green body; sparsely haired; distinctive cylindrical abdomen; pollen-carrying hairs on hind legs; 3-10 mm.

Family: Megachilidae. Robust body; broad, round head and abdomen; usually metallic green or blue; pollen-carrying hairs on underside of abdomen; 5-20 mm.

Family: Colletidae. Slender; almost hairless; black body with yellow or white markings on head, thorax and legs; no pollen-carrying hairs; 5-7 mm.

A Bee or Not a Bee?

There are two major groups of insects that are commonly confused with bees—flies and wasps. In fact, many flower-visiting flies are actuallybee mimics. By mimicking bees in appearance, they are able to gain protection from predators and even act as bee parasites. So how do you tell them all apart?

Fly Identification: Flies have only two wings, while bees have four. Flies have short, stubby antennae with long hairs or feathery antennae and sucking or sponging mouthparts. Many flies have large eyes that almost meet at the top of their heads.

Wasp Identification: Similar to bees, waspshave four wings, chewing mouthparts, a sting, and long antennae. But, while bees are usually very hairy, wasps are usually smooth and almost hairless. Wasps also have a typical, slender “wasp waist” and rarely have pollen-carrying hairs because most are carnivores and don’t eat pollen. Wasps are important predators of many pest insects including cutworms, aphids, and grasshoppers. Additionally, some wasps make paper nests in trees or on buildings.

Now that you know how to tell the difference between bees, wasps, and flies, try identifying these insects. Answers are at the bottom.

© 2010 Tom Murray

©2010 Lynette Schimming© 2008 Gary McDonald

Answers: 1) Wasp 2) Fly 3) Fly 4) Wasp 5) Sweat bee

6) Cuckoo Bee 7) Leaf cutting bee 8) Wasp 9) Fly

©2010 Ken Kertell©2009 Steve NanzLong horned bees (Melissodesspp.)Family: Apidae. Robust; hairy; black body with pale hair bands on abdomen; dense pollen-carrying hairs on hind legs; males have very long antennae; 7-16 mm.© 2009 Kevin Hall© 2009 J.C. Lucier

©2006 Tom Murray

Mining bees (Andrenaspp.)Family: Andrenidae. Black or dull metallic blue or green body; fairly hairy; pollen-carrying hairs on upper parts of hind legs (resemble “armpits”); 6-15 mm.

© 2010 Ted Kropiewnicki

Cuckoo bees (Nomadaspp.)

Family: Apidae. Wasp-like; sparse branched hairs; red or black body with yellow or white markings; relatively thick antennae; no pollen-carrying hairs; 5-15 mm.

©2010 Tom Murray

©2008 Hartmut Wisch©2007 Lynette Schimming

©2004 RKD Peterson

©2008 RKD Peterson©2008 RKD Peterson©2005 RKD Peterson©2004 RKD Peterson©2009 Lynette Schimming©2006 Lynette Schimming

©2008 Lynette Schimming








Acknowledgements: Thank you to GennaBoland for assistance with AutoMontage® photographs and image editing.

  • Solitary; nest in dead twigs and stems.
  • Yellow or white markings on face (females have avertical bar, males have an inverted T).
  • Solitary; nest in the ground; prefer sandy soil.
  • Andrenids are very abundant in the spring as they are one of the first bees to emerge each season.
  • Solitary; nest in natural or man-made holes like beetle tunnels, wood nesting blocks, or reed stems.
  • Use mud or chewed-up leaves/petals for nest walls.
  • Solitary to communal ground nesters.
  • Some are especially attracted to asters, sunflowers, and daisies.
  • Solitary; nest in twigs, stems, and existing tunnels in wood.
  • Carry pollen and nectar in a special storage structure of the digestive system called a crop.
  • Females visit flowers for nectar, but do not collect pollen for their young.
  • Females are cleptoparasites-they lay eggs in nests of other bees thereby stealing the nests and food.

©2010 Tom Murray

Printable version of MSU IPM Biological Controls (PDF)


Products listed alphabetically: Product

Biocontrol Agent

Target Pathogen




Application Method





Tobacco, tomato, lettuce, spinach

Water dispersible granule.


Syngenta Crop Protection P.O. Box 18300, Greensboro, NC 27419 USA. Phone: 1-800-334-9481 www.syngentacropprotection-us.com/


Streptomyces lydicus

soilborne disease

greenhouse and nursery crops, turf

water-dispersible granule


Manufacturer/Distributor: Natural Industries, Inc. 6223 Theall Rd., Houston, TX 77066 USA. Phone: 888-261-4731, FAX: 281-580-4163. www.naturalindustries.com/index.html


Aspergillus flavus AF36

Aspergillus flavus strains that pruduce aflatoxin


sterilized wheat seeds colonized by A. flavus

aerial or ground equipment

Arizona Cotton Research and Protection Council, 3721 East Wier Ave., Phoenix, AZ 85040 USA


Aspergillus flavus NRRL 21882

Strains of the fungus A. flavus that produces aflatoxin


granules containing 0.01% A. flavus NRRL 21882

applied to soil at 1 gram ai/acre once per year, 40-80 days after the peanuts are planted

Circle One Global, Inc. One Arthur Street, PO Box 28, Shellman, GA 39886-0028. Phone: 229-768-2538

All Natural 3-in-1 Garden Insect Spray

Rosemary oil, clove oil, cottonseed oil

Powdery mildew, rusts, leaf spots, bacterial spot and speck, anthracnose, fire blight, greasy spot, scab, brown rot, leaf curl, bunch rot, early late blight and many others.

Fruits, Vegetables & Ornamentals




Pseudomonas chlororaphis63-28

wilt diseases as well as stem and root rots

ornamentals and vegetables grown in greenhouses


Turf Science Laboratories, Inc., 2121 Hoover Ave., National City, CA 91950 USA.

AQ10 Biofungicide

Ampelomycesquisqualisisolate M-10

powdery mildew

apples, cucurbits, grapes, ornamentals, strawberries, and tomatoes

water-dispersible granule


Ecogen, Inc., 2005 Cabot Blvd. West, Langhorne, PA 19074; Phone: 1-215-757-1590; FAX: 1-215-752-2461


Bacillus pumilus QST2808

Asian soybean rust




AgraQuest, Inc., 1530 Drew Avenue, Davis, CA 95616 USA. Phone: 1-530-750-0150, Fax: 1-530-750-0153, www.agraquest.com

Binab T Wettable Powder Biorational Fungicide

Trichoderma harzianum ATCC 20476 and Trichoderma polysporum ATCC 20475

fungi that infect tree wounds

ornamental, shade, and forest trees


as a slurry to the wound

BINAB Bio-Innovation EFTR AB, Florettgatan 5, SE-254 67 Helsingborg, Sweden. Phone: 46-42-16-37-04, Fax: 46-42-16-24-97, www.algonet.se/~binab/index2.html

Bio-save 10LP, 110

Pseudomonas syringae

Botrytis cinerea, Penicillium spp., Mucor pyroformis, Geotrichumcandidum

pome fruit, citrus, cherries, and potatoes

lyophilized product, frozen cell concentrated pellets

pellets added to water to produce liquid suspension, postharvest application to fruit as drench, dip or spray

JET Harvest Solutions, PO Box 915139, Longwood, FL 32791 USA. Phone: 1-877-866-5773, www.jetharvest.com

BlightBan A506

Pseudomonas fluorescens A506

Frost damage, Erwinia amylovora, and russet-inducing bacteria

almond, apple, apricot, blueberry, cherry, peach, pear, potato, strawberry, tomato

wettable powder

bloom time spray of the flower and fruit

NuFarm Inc., 1-708-754-3330, www.nufarm.com


Bacillus subtilis GB03, other B. subtilis ,B. lichenformis, B. megaterium

Rhizoctonia, Pythium, Fusarium,and Phytophthora

Greenhouse and nursery


drench at time of seeding and transplanting or as a spray for turf

Growth Products, Ltd., PO Box 1252, Westmoreland Ave., White Plains, NY 10602 USA. Phone: 1-800-648-7626, Fax: 914-428-2780, Internet: www.growthproducts.com

Contans WG, Intercept WG

Coniothyriumminitans strain CON/M/91-08

Sclerotiniasclerotiorum and S. minor


water dispersible granule


Sylvan Bioproducts, Inc., 333 Main Street, PO Box 249, Saxonburg, PA 16056-0249 USA. Phone: 1-724-352-7520, www.sylvanbio.com

Concern Copper Soap

Copper with fatty acids

Downy mildew, leaf and fruit spots, blights and rusts

Flowers, fruits and vegetables indoor and outdoor



Woodstream Corporation

69 North Locust Street

Lititz, PA 17543


fermentation product of killed Myrothecium verrucaria (killed)

Parasitic nematodes

cole crops, grape, ornamentals, turf, trees

powder and liquid suspension from fermentation

to soil and incorporated by various methods

Valent Biosciences, Inc., 1333 N. California Boulevard #600, Walnut Creek, CA 94596, USA. Phone: 800-6-VALENT. www.valent.com


Bacillus licheniformis SB3086

Dollar spot, low and moderate disease pressure


liquid spore concentrate

standard spray equipment

Novozymes A/S, Krogshoejvej 36, 2880 Bagsvaerd, Denmark. Phone: 45-88-24-99-99, Fax: 45-88-24-99-98; or Novozymes Biologicals, Inc., 5400 Corporate Circle, Salem, VA, 24153.


Frostban A

Pseudomonas fluorescens strains A506 and 1629RS, Pseudomonas syringae742RS

frost-forming bacteria

certain fruits, almond, potato, and tomato crops

two to four spray applications early in growing season

Frost Technology Corporation, 1333 Burr Ridge Parkway, Suite 125A, Burr Ridge, IL 60527 USA.

Frostban B

Pseudomonas fluorescens A506

frost-forming bacteria

certain fruits, almond, potato, and tomato crops

two to four spray applications early in growing season

Frost Technology Corporation, 1333 Burr Ridge Parkway, Suite 125A, Burr Ridge, IL 60527 USA.

Frostban C

Pseudomonas syringae742RS

frost-forming bacteria

certain fruits, almond, potato, and tomato crops

two to four spray applications early in growing season

Frost Technology Corporation, 1333 Burr Ridge Parkway, Suite 125A, Burr Ridge, IL 60527 USA.

Frostban D

Pseudomonas fluorescens 1629RS

frost-forming bacteria

certain fruits, almond, potato, and tomato crops

two to four spray applications early in growing season

Frost Technology Corporation, 1333 Burr Ridge Parkway, Suite 125A, Burr Ridge, IL 60527 USA.


Mint oil, Citric Acid, Glycerol, Citrus Pulp (strained), Fish Oil (edible), Vitamin C (ascorbic acid) and water.

Alternaria, Aspergillus, Botrytis, Bremia, Erysiphe, Microsphaera, Pseudoperonospora, Phytophtora, Sclerotinia, Fusarium Patch, Fairy Ring, Take-all Patch

Turf and ornamentals



Soil Technologies

2103 185th St.,

Fairfield, IA 52556 USA



Agrobacterium radiobacter Strain 84

crown gall disease caused by Agrobacterium tumefaciens

fruit, nut, and ornamental nursery stock

petri plates with pure culture grown on agar

bacterial mass from one plate transferred to one gallon of non-chlorinated water; suspension applied to seeds, seedlings, cuttings, roots, stems, and as soil drench

AgBioChem, Inc., 3 Fleetwood Ct., Orinda, CA 94563, USA. Phone: 1-925-254-0789 or 10795 Byrne Avenue, Red Bluff, CA, 90860 USA. Phone: 1-530-527-8028, www.crowngall.com

GB34 Biological Fungicide

Bacillus pumilus GB34

fungal pests Rhizoctonia and Fusarium

soybean seeds

slurry applied to seeds using specified mechanical seed-treating equipment

Gustafson LLC, 1400 Preston Road, Suite 400, Plano, TX 75093, USA. Phone: 972-985-5617, Fax: 972-985-1696, www.gustafson.com


Garlic oil

Powdery mildew, rust, downy mildew

Ornamental indoor and outside



JH BIOTECH, INC. 4951 Olivas Park Drive, Ventura, CA 93003

Phone: (805) 650-8933 www.jhbiotech.com/


Potassium bicarbonate and surfactants

Powdery mildew and other fungi

Flowers, trees, houseplants, fruits, vegetables and turf



H & I Agritech, Inc.

95 Brown Road, Box 1030

Product Name Ithaca, NY 14850

Green Releaf

Bacillus licheniformis SB3086

many fungal species especially those causing leaf spot and blight diseases

ornamental turf, lawns, golf courses, ornamental plants, conifers and tree seedlings in outdoor, greenhouse, and nursery sites

diluted in water and sprayed on leaves or applied to soil

Novozymes A/S, Krogshoejvej 36, 2880 Bagsvaerd, Denmark. Phone: 45-88-24-99-99, Fax: 45-88-24-99-98; or Novozymes Biologicals, Inc., 111Kesler Mill Rd., Salem, VA 24153, USA; www.novozymes.com

HiStick N/T

Bacillus subtilis MBI600 (rhizobia also in formulation)

Fusarium spp., Rhizoctoniaspp, Aspergillus

soybean, alfalfa, dry/snap beans, peanuts

slurry, damp and dry inoculation of seed

Becker Underwood, 801 Dayton Ave., PO BOX 667, Ames, IA 50010. Phone: 515-232-5907, FAX: 515-232-5961, www.beckerunderwood.com

Kodiak (several formulations)

Bacillus subtilis GB03

Rhizoctoniasolani, Fusarium spp., Alternaria spp., and Aspergillus spp. that attack roots

cotton, legumes

dry powder; usually applied with chemical fungicides

added to a slurry mix for seed treatment; hopper box treatment

Gustafson, Inc., 1400 Preston Rd, Suite 400, Plano, TX 75093 USA. Phone 1-800-248-6907 or 1-972-985-8877; Fax: 1-972-985-1696, www.gustafson.com

MeloCon WG

Paecilomyceslilacinusstrain 251

Plant parasitic nematodes


water dispersible granule

spray, drench, drip irrigation

WF Stoneman Company LLC. PO Box 465, McFarland, WI 53558-0465. billstoneman@charter.net


Bacillus cereus BP01

Uniform plant height, decrease in vegetative growth, larger cotton bolls

cotton plants

aerial and ground spraying

Micro-Flo Company LLC, 530 Oak Court Drive, Memphis, TN, 38117 USA. Phone: 1-800-451-8461, Fax: 901-432-5100, www.microflocompany.com


Erwinia amylovoraHrpNharpin protein.


field, ornamental, and vegetable crops


drench or spray.

EDEN Bioscience Corporation, 3830 Monte Villa Parkway, Suite 100, Bothell, WA 98021-7266 USA. Phone: 888-879-2420 or 425-806-7300, Fax: 425-806-7400, www.edenbio.com


Streptomyces griseoviridisstrain K61

Fusarium spp., Alternaria brassicola, Phomopsis spp., Botrytis spp., Pythium spp., and Phytophthora spp. that cause seed, root, and stem rot, and wilt disease

field, ornamental, and vegetable crops


drench, spray or through irrigation system

AgBio Inc., 9915 Raleigh St., Westminster, CO 80031 USA. Phone: 877-268-2020, Fax: 303-469-9598, www.agbio-inc.com


Agrobacterium radiobacterK1026

Agrobacterium tumefaciens

fruit and nut trees, caneberries, roses, and other ornamental nursery stock

pure culture in pre-sterilized, neutralized, finely divided peat

culture diluted in nonchlorinated water then used as for seed, root, or cutting dips or sprays

New BioProducts, Inc., 4272 NW Pintail Place, Corvallis, OR 97330 USA. Phone: 541-752-2045; Fax: 541-754-3968, www.newbioproducts.com



catenulatum strain J1446

soilborne pathogens that cause seed, root, and stem rot, and wilt disease

ornamental, vegetable, and tree crops


drench, spray or through irrigation system

AgBio Development Inc., 9915 Raleigh St., Westminster, CO 80031; Phone 877-268-2020, 303-469-9221; FAX 303-469-9598. www.agbio-inc.com


Trichoderma harzianumRifai strain KRL-AG2 (T-22)

Pythium spp., Rhizoctoniasolani, Fusarium spp.

trees, shrubs, transplants, all ornamentals, cabbage, tomato, cucumber

granules or wettable powder

granules mixed with soil or potting medium; powder mixed with water and added as a soil drench

Bioworks, Inc., 345 Woodcliff Dr., First Floor, Fairport, NY 14450 USA. Phone: 1-800-877-9443 or 585-641-0581, Fax: 1-800-903-2377 or 585-641-0584, www.bioworksbiocontrol.com

Serenade / Rhapsody/ Serenade Garden

Bacillus subtilis QWT713

powdery mildew, downy mildew, Cercospora leaf spot, early blight, late blight, brown rot, fire blight, and others

cucurbits, grapes, hops, vegetables, peanuts, pome fruits, stone fruits, and others

wettable powder


AgraQuest, Inc., 1530 Drew Avenue, Davis, CA 95616 USA. Phone: 1-530-750-0150, Fax: 1-530-750-0153, www.agraquest.com


Copper octanoate

Powdery mildew, downy mildew, leaf and fruit spots, rusts, fruit rots

Fruits, flowers, vegetables, ornamentals

Flowable concentrate


Gardens alive! inc 5100 Schenley place Lawrenceburg, IN 47025 Company Number: 056872


Bacillus pumilus

powdery mildew, downy mildew, Cercospora leaf spot, early blight, late blight, brown rot, fire blight, and others

cucurbits, grapes, hops, vegetables, peanuts, pome fruits, stone fruits, and others

wettable powder


AgraQuest, Inc., 1530 Drew Avenue, Davis, CA 95616 USA. Phone: 1-530-750-0150, Fax: 1-530-750-0153, www.agraquest.com


Gliocladiumvirens GL-21

damping-off and root rot pathogens especially Rhizoctoniasolani and Pythium spp.

ornamental and food crop plants grown in greenhouses, nurseries, homes, and interiorscapes


granules are incorporated in soil or soilless growing media prior to seeding

Certis USA LLC, 9145 Guilford Road, Suite 175, Columbia, MD 21046 USA. Phone: 1-301-604-7340 or 1-800-847-5620, Fax: 1 301-604-7015, www.certisusa.com

Spot-Less Biofungicide

Pseudomonas aureofaciensTx-1

dollar spot, anthracnose, Pythium, pink snow mold


added directly to sprinkler system

Turf Science Laboratories, Inc., 2121 Hoover Ave., National City, CA 91950 USA.

Stylet-oil, Sunspray Ultra-fine

Mineral oil

Powdery mildew, rust, black spot, Cercospora, Botrytis, Alternaria leaf spot, gummy stem blight, viruses (vector control)

Fruit trees, vegetables, small fruits, turf, roses



JMS Flower Farms, Inc, 4423 5th Place SW, Vero Beach, FL 32968



Bacillus subtilis MBI600

Fusarium spp., Rhizoctonia spp., and Pythium spp. that cause seed and root rots

field, ornamental, and vegetable crops


drench, spray or through irrigation system

Becker Underwood, 801 Dayton Ave., PO BOX 667, Ames, IA 50010. Phone: 515-232-5907, FAX: 515-232-5961, www.beckerunderwood.com

Taegro, Tae-Technical

Bacillus subtilis var. amyloliquefaciens FZB24

Rhizoctonia and Fusarium

Only in greenhouses and other indoor sites on shade and forest tree seedlings, ornamentals, and shrubs. Not permitted for use on food crops.


suspend in water and either drench or dip plants

Earth Biosciences Inc., 106 Somerset Ave., Fairfield, CT 06824, USA.


Sodium carbonate peroxyhydrate and other

Moss, slime molds, algae, Brown Patch, Dollar Spot, Snow Mold, Pythium , Liverwort

Lawns, Ornamental Shrubs, Flowerbeds

and Walkways. Indoor outdoor


Dry spreader

BioSafe Systems LLC

22 Meadow Street

East Hartford, CT 06108


Neem oil

Alternaria, Anthracnose,

Early blight, Leaf blight, Botrytis, Greasy spot, Leaf spot, Post bloom fruit drop, Powdery mildew, Molds, Scabs, Rusts, Shothole

vegetables, fruits, nuts, melons, outdoor ornamental plants and agronomic crops



Certis USA LLC, 9145 Guilford Road, Suite 175, Columbia, MD 21046 USA. Phone: 1-301-604-7340 or 1-800-847-5620, Fax: 1 301-604-7015, www.certisusa.com



Soilborne fungal pathogens causing root diseases


dry powder

added to a slurry mix for seed treatment; hopper box treatment.

Gustafson, Inc., 1400 Preston Rd, Plano TX 75093 USA; Phone 1-800-248-6907 or 1-972-985-8877; FAX 1-972-985-1696. www.gustafson.com


Hydrogen peroxide and other

Algae - Anthracnose - Brown Patch - Black Spot - Botrytis - Copper Spot - Dollar Spot - Downy Mildew - Fairy Ring - Fusarium - Leaf Spot - Pink Snow Mold - Pseudomonas - Pythium - Phytophthora - Powdery Mildew - Rhizoctonia - Rust - Scab - Slime Molds - Smut - Summer Patch - Thielaviopsis - Wilts & Blights - and other plant pathogenic fungal and bacterial spores

Bedding plants, Flowering plants, Roses, Poinsettia, Ornamentals, Nursery stock, Trees, Turf, Cut flowers, Bulbs, Cuttings, Seedlings and Seeds


Spray or drench

BioSafe Systems LLC

22 Meadow Street

East Hartford, CT 16108

Endomycorrhizae to increase plant nutrition and help protect against disease:

Glomus sp.(VAM fungus): Bioscientific (Mycorise) • BioOrganic • Green Releaf(BioReleaf) • Mikro-Tek • Plant Health Care (Mycor) • Biological Crop • Natural Fertilizer • Philom (TagTeam) • Rincon-VitovaAgBio • Roots • Mycorrhizal Applications

Ectomycorrhizae (forest nurseries, urban trees):

Pisolithustinctorius: Rincon-Vitova • Plant Health Care (Mycortrees) • Plant Revolution • AgBio • Mycorrhizal Applications Pisolithus, Rhizopogon mixtures: Roots • Plant Health Care

Microbial Soil Amendments:

New Era Farm Service (composted soil amendments) • Jade Mountain (composting toilet) • Northeast Organics (Turf Cocktail to stimulate microbials in soil) • Lane • AgroDist

Beneficial microorganisms that attack

turf pathogens:

Gardener’s Supply (Green Magic) • Green Releaf (BioReleaf) • Peaceful Valley (Restore) • Wilbur-Ellis (BioTrek) • Bioworks (Turfmate) • Eco-Soil (BioJect) • Soil Technologies (BacPack) • Natural Fertilizer • Plant Health Care (Compete)

Disease-suppressive container mixes or compost:

BioCompEarthgro (Scotts) • Sun-Gro • Southern • Louisiana Pacific • O.M. Scotts (Hyponex) • Paygro


Printable version of Needle Cast Diseases of Conifers (PDF)

Needle Cast Diseases of Conifers

Primary Hosts

Fungus/Disease Name

Infection Period/Fruiting Bodies


Needles Shed Timing

Scots pine, ponderosa pine


Late summer - early fall

Small, gray or black, football-shaped hysterothecia visible to the naked eye. When mature, these protrude slightly, and the epidermis ruptures to form a slit.

Winter- early spring

Yellow and reddish-brown spots on the needles, some of which may have yellow margins. Eventually, the entire needle will turn yellow, then reddish brown.

Mid-late spring

Ponderosa, lodgepole pines


Mid - late summer

Long black slit in epidermis near needle base

Early spring

Needles red-brown at tips, base remain green, witches brooms

12-20 months after infection

Ponderosa, Austrian, mugo pines




Black dots erupting thru epidermis in bands

Late summer - early fall

Distinct red transverse banding on tan needles


Lodgepole pine , limber pine


Late spring - early summer

Small depressions in leaf surface

Early – late spring

Dead, reddish-brown, then straw colored.


Douglas fir


Late spring – summer

Tan slits on underside of needles

Late summer - early fall

Yellow lesions followed by purple-brown spots and bands


Douglas fir

Swiss Needle cast

Late spring – early summer

The tiny black dots emerge through the stomata in rows on the underside on either side of the midrib.

Within a year

New needles become yellow overall although they occasionally turn brown general chlorosis or red-brown tips

1-3 years after infection




Dark, elongate pycnidia down center of lower surface of needles . Brown line on upper surface. Pustule like.


Needles become pale and patchy green and slowly turn brown.

2 years after infection


Rhizosphaera/ Stigmina

Spring – Fall

Black dots in stomata in rows

Late winter-early spring

Yellow to reddish-purple to brown

Late summer - Fall


Sudden Needle Drop


Black specks (perithecia) on twigs

Unknown (late winter – early spring)

Older needles are affected. Turn yellow to reddish-purple to brown similar to other spruce diseases

Unknown (late summer – early fall)

All species

Seasonal Needle Cast



Inner most needles suddenly turn brown. Needle retention depends on species and environment.


Printable version of Powdery Mildew Colorado State Extension (PDF) 

Powdery Mildews

2.902 Fact Sheet No. Gardening Series|Diseases

by B. Edmunds and L.P. Pottorff*

Powdery mildews are one of the most widespread and easily recognized plant diseases. They affect virtually all kinds of plants: cereals and grasses, vegetables, ornamentals, weeds, shrubs, fruit trees, and broad-leaved shade and forest trees. In Colorado, powdery mildews are common on ash, lilac, grape, roses, turfgrass, vegetables (such as cucurbits and peas), euonymus, cherry, apple, crabapple, pear and Virginia creeper, among others.


Even though there are several types of powdery mildew fungi, they all produce similar symptoms on plant parts. Powdery mildews are characterized by spots or patches of white to grayish, talcum-powder-like growth. Tiny, pinhead-sized, spherical fruiting structures that are first white, later yellow-brown and finally black, may be present singly or in a group. These are the cleistothecia or overwintering bodies of the fungus.

The disease is most commonly observed on the upper sides of the leaves. It also affects the bottom sides of leaves, young stems, buds, flowers and young fruit. Infected leaves may become distorted, turn yellow with small patches of green, and fall prematurely. Infected buds may fail to open.

Conditions That Favor the Disease

The severity of the disease depends on many factors: variety of the host plant, age and condition of the plant, and weather conditions during the growing season.

Powdery mildews are severe in warm, dry climates. This is because the fungus does not need the presence of water on the leaf surface for infection to occur. However, the relative humidity of the air does need to be high for spore germination. Therefore, the disease is common in crowded plantings where air circulation is poor and in damp, shaded areas. Incidence of infection increases as relative humidity rises to 90 percent, but it does not occur when leaf surfaces are wet (e.g., in a rain shower). Young, succulent growth usually is more susceptible than older plant tissues.

About the Fungi

Powdery mildews are host specific – they cannot survive without the proper host plant. For example, the species Uncinulanecator, which causes powdery mildew on grape and linden, does not attack lilac. Similarly, Microsphaeaalniaffects elm, catalpa, lilac and oak but not turfgrass.

Powdery mildews produce mycelium (fungal threads) that grow only on the surface of the plant. They never invade the tissues themselves. The fungi feed by sending haustoria, or root-like structures, into the epidermal (top) cells of the plant. The fungi overwinter on plant debris as cleistothecia or mycelium. In the spring, the cleistothecia produce spores that are moved to susceptible host tissue by splashing raindrops, wind or insects.



Several practices will reduce or prevent powdery mildews. Many plants, such as roses, vegetables and Kentucky bluegrass, are developed to be resistant or tolerant to powdery mildew. Inquire about resistant varieties before a purchase. If resistant

Quick Facts

  • Powdery mildew is one of the most widespread and easily recognized plant diseases.
  • Powdery mildews are characterized by spots or patches of white to grayish, talcum-powder-like growth.
  • Powdery mildews are severe in warm, dry climates
  • Many plants have been developed to be resistant or tolerant to powdery mildew.
  • Succulent tissue is more susceptible to infection. Once the disease is a problem, avoid late summer applications of nitrogen fertilizer.
  • Plant resistant varieties if available.
  • Chemicals are most effective when combined with cultural controls.

©Colorado State University Extension. 10/99. Reviewed 5/09.


*Colorado State University Extension regional specialist, commercial greenhouse and nurseries, Adams County. Originally written by Laura Pottorff, former plant pathologist and horticulturist, Integrated Pest Management Program, Jefferson County. 5/09

varieties are unavailable, do not plant in low, shady locations.

Once the disease becomes a problem:

  • Avoid late-summer applications of nitrogen fertilizer to limit the production of succulent tissue, which is more susceptible to infection.
  • Avoid overhead watering to help reduce the relative humidity.
  • Remove and destroy all infected plant parts (leaves, etc.). For infected vegetables and other annuals, remove as much of the plant and its debris in the fall as possible. This decreases the ability of the fungus to survive the winter. Do not compost infected plant debris. Temperatures often are not hot enough to kill the fungus.
  • Selectively prune overcrowded plant material to help increase air circulation. This helps reduce relative humidity and infection.


If cultural controls fail to prevent disease buildup or if the disease pressure is too great, an application of a fungicide may be necessary. These include:

  • sulfur
  • neem oil (Rose Defense, Shield-All, Triact)
  • triforine (Ortho Funginex), ornamental use only
  • potassium bicarbonate (Kaligreen, First Step)

Chemicals are most effective when combined with cultural controls. Apply fungicides at seven to 14-day intervals to provide continuous protection throughout the growing season. Follow the instructions on the fungicide label for use on specific plant species, varieties, rates to be used, timing of applications, and waiting periods before harvest.

An alternative nontoxic control for mildew is baking soda (similar to the potassium bicarbonate listed above) combined with a lightweight horticultural oil (Sunspray). Researchers at Cornell University have discovered the fungicidal properties of this combination against powdery mildew on roses. Applications of one tablespoon baking soda plus 2.5 tablespoons of Sunspray oil in 1 gallon of water are still experimental. Use it at your own risk.

Colorado State University, U.S. Department of Agriculture and Colorado counties cooperating. CSU Extension programs are available to all without discrimination. No endorsement of products mentioned is intended nor is criticism implied of products not mentioned.

Printable version of Raspberry Cane Borer New Hampshire (PDF)

Raspberry Cane Borer


Though damage from the raspberry cane borer is often seen, the insect itself is rarely

recognized as a pest. It usually causes only slight or occasional injury, although, when abundant,

it can cause considerable damage. It is easy to control.


The adult cane borer is a slender, black beetle with long, black antennae, black head and

yellow prothorax. Adults are about one half an inch long. The larvae are legless, light-colored

borers found within the stem. Fully grown larvae are about 3/4 inch long.

Life Cycle

This insect has a two-year life cycle. Adults emerge beginning

in June and females lay eggs in the pith of new raspberry

growth, about six inches from the tip of the cane. The female

beetle then makes two rows of punctures around the cane, one

just above and one just below the egg-laying point. This

causes the tip of the new cane to wilt. The egg hatches in

early July and the larva burrows slowly down the cane, passing

the first winter within and inch or two of the girdle. During

the second year the larva burrows down to the crown and passes the second winter at or

below ground level. It completes its development the following spring and pupates in the soil.


Chemicals are not necessary to control this pest. Cut girdled canes an inch or so below the

girdle and burn them soon after cane borer damage appears. Attacked canes wilt, making the

damage easy to spot. Eliminating wild raspberries nearby will reduce damage. Since the life

cycle requires two years to complete, regular pruning usually keeps the population in check.

Visit our website: ceinfo.unh.edu

UNH Cooperative Extension programs and policies are consistent with pertinent Federal and State laws and regulations

on non-discrimination regarding age, color, handicap, national origin, race, religion, sex, sexual orientation, or veterans status.

Reviewed and amended by Dr. Alan Eaton, UNH Cooperative Extension Entomology Specialist, 9/00

Family, Home & Garden Education Center

practical solutions to everyday questions

Toll free Info Line 1-877-398-4769

M-F . 9 AM - 2 PM

Cane borer damage

Printable version of Spider Identification and Management MSU Montguide (PDF)

Spider Identification and Management

by Gary L Jensen, Will Lanier and Catherine E. Seibert

Spider biology. How to identify house or comb-footed, orb weave, funnel web, aggressive house, recluse, wolf, jumping and crab or ambush spiders.

MT199210 AG Reviewed 3/05

Many people fear spiders more than household insects like ants, cockroaches, crickets, and other common arthropods. This fear often is caused by a lack of information about or experience with spiders. A report by television, radio or newspaper that a person has been bitten by a black widow or a brown recluse spider often triggers a flood of queries. People call or submit samples to county agents, health departments or extension specialists requesting information about these creatures.

For example, in spite of all the publicity it has been given, the brown recluse spider is not yet known to inhabit Montana, yet bites by other spiders are often misdiagnosed as brown recluse bites. And while black widow spiders are common in Montana, much of the fear concerning them is not warranted despite their unsavory reputation.

County agents and health officials can do a better job of dispelling fears about spiders if they have some knowledge about spider identification and biology.

Spiders contrasted to insects

Spiders differ from insects in several respects. They have four pairs of legs, no antennae, no wings, and only two body regions. The head and thorax are combined and called the cephalothorax. The cephalothorax is attached by a narrow pedicel to an unsegmented abdomen. The abdomen has spinnerets at the posterior end, from which silk for spider webs is spun. By contrast, all adult insects have three pairs of legs, one pair of antennae, and three body regions: head, thorax and segmented abdomen which has no spinnerets. Many adult insects have one or two pairs of wings.

All spiders are predators and will eat one another. A few will also scavenge. They are numerous and probably play a useful role in keeping insects and other arthro-pods in check. Insects, on the other hand, feed on nearly anything organic: plants, animals, wood, garbage, stored products, etc. Some insects are highly beneficial, others are pests, and others are neither.

Spider biology

Female spiders are usually larger than males and have a pair of appendages on the head called pedipalps that resemble legs. After mating, female spiders spin silken egg sacs in which they lay masses of eggs. After some time, young spiderlings hatch and emerge from the egg sac. They grow by periodically molting or shedding old skin. Spiderlings molt from four to twelve times before reaching the adult stage. Young spiders resemble adults, living and feeding in the same environment. Spiders catch and feed on many kinds of insects and other arthropods.

Spider mouth parts are quite different from insect mouth parts. They have a pair of pincers, called chelicerae, which have openings at the tips connected to ducts leading from poison glands. While all spiders have poison glands, only a few are poisonous to humans. When spiders capture prey, their bite injects venom and digestive fluids, paralyzing their victim. While the prey is immobilized, the spider sucks out the liquefied, digested tissues, leaving only an empty shell. Other spiders crush the body of their prey, bathe the tissues with digestive fluid, suck up the digested liquid, and continue chewing and rolling the body until only a little ball of indigestible material remains.

Spider identification

About 50,000 species of spiders have been described. While one person is not able to identify all spiders, county agents, health officials and others can easily learn to identify important spiders, just as people learn to recognize poisonous snakes and poisonous plants.

The only truly poisonous spiders in Montana are the black widow, a very docile, non–aggressive spider, (unless the female is protecting the egg sac), and the aggressive house spider. Even though the brown recluse spider has not been found in Montana, county agents and others should be familiar with certain distinguishing characteristics so that they can quickly eliminate it when spiders are brought to them for identification. Spider families are easily identified by the position and number of eyes, the overall shape,

* Extension Integrated Pest Management Specialist (retired), Insect Diagnostician, and Herbarium Collection Manager and Ext. Plant Taxononist, Montana State University, respectively. All drawings by Catherine E. Seibert



length of legs and form of the spinnerets. If a person is bitten by a spider and has reason to seek medical attention, it is important to have a specimen of the suspect spider to aid in identification.

Spiders around the home are found around windows, screens and especially around outside lights, where insect prey are attracted. The first step in identifying a spider is to determine if it is associated with a web. This MontGuide provides a pictorial guide for determining some important common species and families using conspicuous characteristics.

Web spinning spiders

Black widow spiders

The black widow spider and its relatives in the genus Latrodectus are easily recognized by the hourglass marking on the underside of the abdomen. (See illustration on this page.) This marking is reddish or orange on live specimens, but loses its color when preserved in alcohol. Black widow spiders get their name from the fact that the female frequently eats the male after mating, a practice not uncommon to several other species of spiders.

There are probably at least two species of black widow spiders in Montana—the northern black widow, Latrodectusvariolus, and the western black widow, Latro-dectushesperus. They are distinguishable by their color markings.

The western black widow female’s body is about half an inch long and the male is less than half this size. Females have a complete hourglass marking on the underside of the abdomen, which is usually completely black except for a small reddish spot near the tip. Males of the western black widow are usually light brown whereas males of the other species of Latrodectus are generally black. Males have three diagonal pale stripes on each side of the abdomen.

The northern black widow spider is similar to the western black widow except the hourglass marking on the underside of the abdomen is incomplete or split into two triangles. The abdomen of the female is black with a row of reddish spots along the top and diagonal whitish bands on each side. Males have four diagonal whitish bands on each side of the abdomen.

The bite of both the western and northern black widow is a neurotoxin and is very painful. The pain occurs less at the actual bite but rather in the abdomen and limbs. Physiological effects are an accelerated heart beat, increased blood pressure, breathing difficulties, and paralysis. When death occurs, it is due to suffocation. Although the bite of a black widow is rarely fatal it is important to seek medical attention. Antidotes are commercially available.

House spiders

House spiders are among the most common spiders found in buildings. Two of their lateral eyes touch each other on each side of the cephalothorax and are well separated from the other four eyes. Female house spiders have bodies which are l/8 to 3/8 inches long and the abdomen is often covered with dirty whitish or brownish hairs arranged somewhat like chevrons. House spiders spin irregular sheet webs in protected places in the corners of rooms, ledges, windows and under furniture. Unlike black widow spiders, males and females are often observed living together in the same webs. Webs of house spiders often have dead insects entangled in or lying beneath them.

Some common household spiders, Genus Steatoda, are in the same family as the black widow, but are not poisonous. Adult females resemble the black widow in size and shape; however, there is no red hourglass marking on the underside of the abdomen and there is often a whitish T-shaped marking on the topside of the abdomen.

Orb-weaver spiders

Orb-weaver or garden spiders are generally large, with bodies l/2 to 1 inch long. They often have conspicuous black, white, yellowish or orange markings. These common spiders are often seen in late summer or fall. They are able to construct large, conspicuous webs with a central hub from which spokes radiate. All this is constructed in less than an hour. The female sits in the hub, waiting to detect movement that signals prey has been captured. After mating, the female seeks a protected place to lay a cluster of eggs, some 300 to 800, which will hatch the following spring.

Funnel web spiders

Funnel web spiders all have eight eyes about the same size and slightly separated, bodies about l/2 inch long, and usually two dark longitudinal stripes on a grayish cephalothorax. The most distinguishing characteristic is a long posterior pair of spinnerets. Funnel web spiders spin flat webs of silk which extend into tubes or funnels into which the spiders retreat for protection, hence the name. The webs are often found


Western Black Widow

Steatoda sp., House Spider

Family Theridiidae

“House or Comb-footed Spiders”

Medium to small sized, glossy spiders with globular abdomens, thin legs bearing few spines, and eight relatively large, protuberant eyes. House spiders, except for the “widows,” have two of the lateral eyes touching each other on each side and well separated from the other four.


Northern Black Widow


in shrubbery near buildings, or in the angles of windows, doors or buildings. They reach the peak of their population in late summer and fall and often enter buildings at that time. Most funnel-weavers die after the first frosts. Winter is passed in the egg stage.

Aggresive house spider

The aggressive house spider, Tegenariaagrestis, is becoming one of the most common spiders in the Northwest. This spider was first reported in the Seattle area in 1930. It is a prevalent spider in basements and in window wells of houses. It rarely climbs vertical surfaces and is usually found only on the ground or lower floors. Experts have called it the aggressive house spider because it bites with little provocation when cornered or threatened. The aggressive house spider is important medically because of its ability to cause necrotic spider bites. (A necrotic bite causes tissue to die.) The aggressive house spider is a long–legged, swift running member of the funnel web spider family. The brown abdomen has a distinctive yellowish chevron pattern. The legs are a uniform brown without the darker brown bands that other nonpoisonous funnel web spiders have.

Spiders that don’t spin webs

Brown recluse spiders

Brown recluse spiders are easily recognized by a combination of two characteristics: a dark fiddle or violin-shaped marking on the top side of the tan cephalothorax, and six eyes arranged in three pairs forming a semicircle. Most other spiders have eight eyes variously arranged. Adult female brown recluse spiders are about l/2 inch long (legs excluded); males are somewhat smaller. Both female and male brown recluse spiders can bite people and inject venom. Individuals react differently to bites. A stinging sensation is usually followed by intense pain. A small blister arises and a large swollen area around the bite becomes congested and swollen. While bites of the brown recluse are generally not fatal, they result in a local necrotic lesion that heals slowly, leaving an ugly scar. There are other spider bites that give a similar reaction, and these are often misdiagnosed by well-meaning physicians as brown recluse spider bites.

Wolf spiders

Wolf spiders are medium to large spiders, and are usually hairy, brown or black, with long legs adapted for running. They have good eyesight—an adaptation for chasing down their prey, paralyzing it and feeding. Webs are not used by wolf spiders. Female wolf spiders carry the egg sac attached to their spinnerets until the eggs hatch. They then carry the young spiderlings about on their backs for a time. Some of the largest spiders encountered in Montana are in this group. This group is very mobile and may be found moving into houses in the fall in search of prey.

Family Loxoscelidae

“Recluse Spiders”

Distinctive violin-shaped marking on the cephalothorax. The six eyes are arranged in three pairs forming a semicircle.

Family Araneidae

“Orb Weaver Spiders”

Legs rather stout and spiny. All eight eyes small, sub-equal, and seemingly grouped into pairs. Web is an orb with a closed hub. Their retreat is often away from the web.


“Aggressive House Spider”

Swift-running spider distinguished from non-poisonous funnel web spiders by chevron shape on its abdomen and legs which are not banded like other funnel web spiders.

Redrawn from Levi and Levi, 1968

Redrawn from Katson, 1978

Family Lycosidae

“Wolf Spiders”

Eyes arranged in three rows with four large eyes on top and front of head and anterior, slightly curved row of four small eyes. Females carry the globular egg sac attached by the spinnerets. The fourth pair of legs is the longest and frequently held stretched out behind the spider.

Family Agelenidae

“Funnel Web Spiders”

Spinnerets long, two segmented, and conspicuous. Eyes small, sub-equal, and arranged in two relatively short rows. Web is sheet or platform-like with a tubular retreat leading off from the center or one edge.

Copyright © 2005 MSU Extension Service

We encourage the use of this document for nonprofit educational purposes. This document may be reprinted if no endorsement of a commercial product, service or company is stated or implied, and if appropriate credit is given to the author and the MSU Extension Service. To use these documents in electronic formats, permission must be sought from the Ag/Extension Communications Coordinator, Communications Services, 416 Culbertson Hall, Montana State University–Bozeman, Bozeman MT 59717; telephone (406) 994-2721; E-mail – publications@montana.edu. To order additional publications call your local county or reservation Extension office, or visit www.montana.edu/publications

The U.S. Department of Agriculture (USDA), Montana State University and the Montana State University Extension Service prohibit discrimination in all of their programs and activities on the basis of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital and family status. Issued in furtherance of cooperative extension work in agriculture and home economics, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Douglas L. Steele, Vice Provost and Director, Extension Service, Montana State University, Bozeman, MT 59717.

Jumping spiders

Jumping spiders, like wolf spiders, do not spin webs to capture prey, but rely on quickness and visual acuity. Jumping spiders and wolf spiders have two eyes much larger than the other six, probably an adaptation to help them better see their prey. Jumping spiders are small to medium sized spiders, usually stout bodied, short legged and hairy. They frequently have contrasting black, reddish, or yellowish markings. They are very agile, pouncing and feeding on small insects about the home. They are often seen on screens or near doors or windows.

Crab spiders

Crab or ambush spiders are somewhat crab-like in shape and walk sideways or backward. They are medium sized and often brightly colored, with abdomens that are usually wide at the posterior end. The two front pair of legs are usually longer and stouter than the two hind pair and crab spiders often hold their legs poised to trap insect prey. They have eight relatively small, well spaced, light colored eyes. Crab spiders are usually found outside in gardens and landscaping where they spin no webs but forage for their prey or lie in ambush on blossoms or other parts of plants. They are able to gradually change colors to match flowers for camouflage.


Spiders are beneficial, preying on insects, so control measures should only be used in situations where they become intolerable—for instance, where black widow or other spiders pose a threat to individuals or pets. A broom or vacuum cleaner used to dislodge and move outside or crush spiders will suffice. Keeping debris and wood piles away from living quarters will aid in limiting food sources and spider havens. Spiders are often found outside under eaves and in corners of residences. By carefully manipulating a broom, one can remove the spiders and relocate them away from the house.


Akre, R. D. and Myhre E. A. 1991. Biology and Medical Importance of the Aggressive House Spider, Tegenariaagrestis, in the Pacific Northwest. Department of Entomology, Washington State University, Pullman, WA.

Kaston, B.J. 1978. How to Know the Spiders, third ed. Wm C. Brown Company Publishers. Dubuque, Iowa. 272 pp.

Jones, D. 1983. The Larousse Guide to Spiders. Larousse & Company, Inc. New York, N.Y. 320 pp.

Levi, H.W. and L.R Levi 1968. A Guide to Spiders and Their Kin. Golden Press. New York, N.Y. 160 pp.

Family Salticidae

“Jumping Spiders”

Square-fronted cephalothorax bearing four very large anterior eyes. Legs usually short and stout with the first pair sometimes enlarged. Diurnal.

Family Thomisidae

“Crab or Ambush Spiders”

First and second pair of legs distinctly longer and stouter than the third and fourth. Abdomen usually broad at the posterior. Crab spiders are commonly seen on flowers, do not construct a web, and are typically brightly colored.DOWNLOADEWEFREE


For more online MontGuides, visit http://www.montana.edu/publications

File under: Insects and Pests

E-5 (Household)

Reviewed March 2005

(2000 03/05 GM)

Printable verison of The use of BT for Spruce Bud Worm (PDF)

Bt biopesticide – marvel or mistake?

Conventional pesticides such as DDT and organophosphates have not only become less

effective as target insect populations evolve resistance, but have killed non-target predators

and parasites that otherwise keep pest insects in balance. Thus, under some conditions, pest

populations have exploded to uncontrollable levels, decimating whatever crops or gardens

they happen to feed upon. Furthermore, these persistent pesticides have accumulated

throughout aquatic and terrestrial food webs (connected food chains within an ecosystem),

creating ecological imbalances and impairing human health. Global concerns regarding

pesticide resistance, environmental degradation, and human health problems have led to the

development of biologically based, narrow-spectrum pesticides with fewer long-term hazards.

Over the last several decades, more farmers, forest and landscape managers, and gardeners

have turned to these more environmentally friendly methods of pest control, including Bt.

An introduction to Bt

Bt is an acronym for Bacillus thuringiensis, a naturally occurring species of bacteria found

world-wide in the soil and on plants. Nearly 100 years ago, this bacterium was discovered to

have pesticidal properties if consumed by the larvae of specific insects. Many subspecies,

varieties, and strains of Bt have been identified since then, and it’s likely many others have

yet to be discovered. Though genes from Bt have also been used in genetically modified

organisms, this article will focus only on the use of the microbe as an applied insecticide.

The strains of Bt characterized so far affect members of three insect Orders: Lepidoptera

(butterflies and moths), Diptera (mosquitoes and biting flies), and Coleoptera (beetles).

Commercially-available, EPA-registered Bt products include:

B.t.aizawai(Lepidoptera) – used for wax moth larvae in honeycombs

B.t.israelensis(Diptera) – frequently used for mosquitoes (see sidebar at end)

B.t.kurstaki(Lepidoptera) – frequently used for gypsy moth, spruce budworm, and

many vegetable pests

B.t. san diegoand tenebrionis (Coleoptera) - frequently used for elm leaf beetle,

Colorado potato beetle

B.t.kurstakiis the most commonly used Bt formulation, as it will kill many leaf-feeding

larvae on vegetables, shrubs, fruit trees and conifers. There is abundant scientific literature

on this biopesticidal organism.

Other Bt isolates have been characterized but not yet registered by the EPA. These include:

B.t.galleriae(Coleoptera) – used on Japanese beetles

B.t.japonensisand kumamotoensis – (Coleoptera) – used on several turf beetle species

Local isolates of Bt probably represent an underutilized, yet powerful, biological control

resource. In China, 30 new strains of Bt were isolated from drylands, gardens, and rice fields;

from these, one highly toxic strain was able to kill 100% of treated diamondback moth larvae

(Plutellaxylostella). Similarly high toxicities were found in ten new Bt strains isolated from

leaf and soil samples in Poland and in four new strains discovered in Mexico. Local bacterial

populations have the advantage of being adapted to local insect host; thus, it is logical to

expect to find powerful biocontrol agents in the pest’s backyard.

Mode of action

Bacillus thuringiensis strains produce crystalline proteins (called δ-endotoxins) that, when

consumed by particular insect larvae, have a poisonous effect upon the lining of the gut.

While some of the toxicological details are still a topic of scientific debate, we do know that

the crystalline proteins manufactured by the bacteria are toxic, causing the cell membranes

in the gut to split open and thus kill the larvae. The specificity of these toxins for insect

physiology means that other animals are not affected by the bacteria.

Bt found naturally on or applied to leaf surfaces must be ingested by the feeding form or an

insect (the larvae) to have an effect; in other words, Bt has no effect on adult insects.

Susceptible larvae that ingest the toxin are not killed immediately, but die over the next few

days. They do stop feeding, however, and thus plant damage is halted. Larvae that survive

the toxin may be more susceptible to other environmental stresses, such as cold temperatures

or low levels of botanical insecticides. This type of synergistic effect underscores the

importance of utilizing Bt as part of an integrated pest management plan.

Some insects have already developed resistance to Bt, most importantly the diamondback

moth (Plutellaxylostella), regarded as one of the most destructive crop pests worldwide. It

is a particularyresiliant species, reported to be the first insect to develop resistance to DDT

and almost every other synthetic insecticide. Bt-resistant insects apparently are able to

detoxify the bacterial proteins quickly and thus survive. Interestingly, Bt resistance appears

to harm the insect’s fitness when Bt is not present; in other words, resistant individuals do

not reproduce well so that resistance is quickly lost in the larger population when Bt is not

applied. This “resistance instability” may explain why Bt resistance is uncommon in pest

insect populations.

Human health and safety

All strains, subspecies, and varieties of Bt used as pesticides must be extensively tested for

both human and environmental safety. Regulatory agencies, such as the USEPA, require

thorough evaluations of the active microbial ingredient before they can be registered as

pesticides. Bacillus thuringiensis has been extensively used for four decades in biopesticidal

formulations due to its environmental and human health records.

Bt is considered to be “practically non-toxic” to humans and other vertebrates. It can cause

a “very slight irritation” if inhaled, and can cause eye irritation. These acute effects are

considered to be minor; there are no chronic toxicities. Bt is not carcinogenic, mutagenic, or

teratogenic: in other words, it does not cause cancer, induce chromosomal mutations, or

lead to birth defects in exposed animals.

Bt does not persist in the brains, lungs, or digestive systems of animals including humans.

While Bt has been found in fecal samples of exposed greenhouse workers, no GI symptoms

were associated with its presence. In fact, Bt appears to be a normal component in the feces

of vegetable-consuming animals, where it apparently causes no problem. Since Bt is a

normally-occuring bacteria often found on leaf surfaces, this should not be a surprise or a

cause for concern.

Like the active bacterial ingredient, the inert ingredients in Bt formulations have also been

studied and modified for safety. Newer formulations employ preservatives, like sorbitol, that

are safer than the xylene used decades ago. Likewise, granular and microcapsule

formulations reduce the inhalation hazard. Volatile agents associated with some Bt

formulations likewise do not appear to constitute a significant health hazard.

In the 50 years that Bt has been used for insect control, there have been few reports of

human pathogenicity, suggesting that the commercially available products are free from non-

Bt microbes and can be safely used around people. In contrast, there are often significant

human health risks associated with the pest insects themselves. Many larvae are protected by

urticating (barbed) hairs, which can irritate skin and mucous membranes. Dermatitis,

conjunctivitis, and/or respiratory disorders have resulted in people who have been in contact

with pine processionary moth Thaumetopoeapityocampa, cypress processionary moth

Thaumetopoeawilkinsoni, and grapeleafskeletonizerHarrisinabrillians.

Environmental and ecological impacts

In addition to their excellent record on human health, Bt products are globally recognized by

researchers in many disciplines as an environmentally safe means of controlling pest insects.

There is an extensive and reliable body of science demonstrating the environmental safety of

Bt, allowing governmental and health organizations to recommend their use on a variety of

landscapes worldwide.

Specifically, no danger has been found to aquatic communities accidentally exposed to Bt

(but see sidebar) or to non-target organisms including beneficial insects, amphibians, fish,

and mammals. A number of researchers have demonstrated the general safety of Bt

formulations to natural predators of pest insects. By and large, these predators belong to

different orders than those affected by most Bt formulations, including spiders (Araneae),

ladybugs (Coleoptera), true bugs (Hemiptera), and ants (Hymenoptera).

There are few reports of Bt lethality upon non-target organisms, such as leaf-feeding

caterpillars. Another researcher has suggested that clay soils may bind the bacterial toxin,

increasing its environmental persistence and possible toxicity to non-target species. Though

the preponderance of the evidence does not agree with these reports, all researchers concur

that Bt monitoring must continue to explore these exceptions and to modify Bt usage as


Urban use

Increasingly, land managers are recognizing the environmental advantages of reduced

chemical treatments in urban areas. Given their extraordinary record in human and

environmental health and safety, Bt products are increasingly applied to urban parks and

landscapes to control gypsy moth (Lymantria dispar), cypress and pine processionary moth

(Thaumetopoeawilkinsoniand Thaumetopoeapityocampa), fall webworm (Hyphantriacunea)

and other nuisance insects. These insects are of particular concern because of their abilities

to denude trees, invade woodpiles, houses, and vehicles in search of pupation sites (fall

webworm), and cause human health problems as mentioned earlier.

Bt use in urban areas requires a significant public education effort. This was illustrated

several years ago when citizens and environmental groups became upset with the aerial

spraying done in parts of Oregon and Washington to control invasions of gypsy moths

(Lymantria dispar) and attempted to get an injunction to halt spraying. The presiding judge

found no scientific proof that Bt was hazardous to people and that the eradication of the

moth populations was of greater environmental concern. Obviously, close communication

with the public is critical when Bt products are used, so that environmental and health

concerns can be addressed. In addition, governmental organizations must be proactive in

enforcing safety regulations and establishing buffer zones in populated areas to reduce

perceived risk and engender citizen trust.

Unfortunately, some gray literature (i.e. not peer-reviewed) ignores the decades of scientific

research on Bt and instead uses scare tactics against Bt. These unbalanced articles serve only

to upset the general public and do not advance either the research, or the discussion, that

must continue to take place regarding Bt and other biopesticides. It is naïve to assume that

growers and landscape managers will give up Bt and simply sit back to watch their livelihood

collapse; if safe and practical alternatives are not available, they will resort to conventional

methods. This is not the direction we need to move.

Bt as part of an Integrated Pest Management (IPM) program

Like any other pest control method, Bt works best as part of an integrated management plan.

The philosophy of such a plan is to reduce pests to acceptable levels, not to eliminate them

completely. As we’ve discovered – much to our detriment - attempts to exterminate pests

result in resistant pest populations and environmental degradation.

Bt has become a cornerstone of IPM systems, accounting for more than 90% of the biological

insecticides currently used. Though Bt has been used successfully by itself, the practice of

IPM generally incorporates Bt, with other biological, cultural, mechanical, and chemical

controls. A great deal of research worldwide has explored the use of Bt in concert with these

associated methods:

Cultural: Crop rotation; minimium tillage; shelter strips

Mechanical: Removal of pest (eggs and larvae); removal of infested materials

Biological: Parasitoids; pathogens, including Bt, fungi, granulosis virus and

nucleopolyhedrosis virus; predators

Chemical: Botanical insecticides such as neem; pheromone baiting/mating disruption;

pyrethrins and pyrethroids

Practical considerations

Like any other living organism, Bt activity is affected by environmental factors including

temperature, rainfall, pH, and sunlight. Bt applied to leaf surfaces, for example, can be

degraded by solar UV or washed off by irrigation or rainfall. Many of these limitations have

been addressed through the development of new Bt formulations that protect the organism

from deactivation. Still, there are other factors that influence effectiveness of this

biocontrol agent.

Only the feeding larval stage is susceptible to Bt, and thus timing of application is of

paramount importance. While this may be during the spring for many leptidopteran pest

species, for coleopteran pests in turf application is only effective in the fall. Cold weather

decreases effectiveness, perhaps because larval feeding activity is reduced.

Location of the target insect also influences Bt effectiveness. Boring insects, though

susceptible to Bt in laboratory trials, can escape Bt exposure if feeding in protected sites.

Likewise, it is difficult, if not impossible, to spray the crowns of tall trees from the ground.

In such cases, a cherry-picker could be used for spraying individual trees, but larger areas are

more effectively managed through aerial spraying.

As with any other pesticide, Bt must be considered as an option, not a magic bullet, for pest

management. Consumer education is critical in this regard to avoid improper or

overapplication of Bt. Misapplication of Bt at the wrong time or on the wrong species can

lead to pest resistance.

Economic feasibility

In its infancy, use of Bt was costly to produce and to apply; while formulation is still

expensive, new production techniques have been developed that promise to lower the cost in

developing countries. Bt is more cost effective to use now, since application costs have

decreased. Proponents hope that the environmental and human health benefits would more

than offset the economic costs.

Indeed, the economic comparisons between conventionally managed and IPM (including Bt)

fields have demonstrated that not only was insect damage reduction approximately the same,

but that IPM net profits were greater because of reduced insecticide costs. Though not

included in these studies, the more intangible benefits associated with Bt-treated fields—such

as reduction in pesticide resistance, less environmental damage, fewer human health risks—

cannot be ignored and must be emphasized.

The big picture

There is no question that broad-spectrum, conventional pesticides can cause more problems

than they solve. Not only is the pest killed, but so too are the beneficial predators and

parasites, leading to future outbreaks of resistant pest populations. The negative, longlasting

effects of these pesticides on human and environmental health should not be ignored

or considered collateral damage.

Once insects become resistant to chemical pesticides, the usefulness of that compound is

finished, at least temporarily. The elegance of biocontrol systems, like Bt, is that the

pesticide is a living organism – one that can evolve as its host becomes resistant. New strains

of Bt and related species are discovered routinely. These specifically-targeted compounds

are considered by the scientific community to be environmentally friendly, with little or no

effect on humans, wildlife, pollinators, and most other beneficial insects. We continue to

discover what we’ve always known—that it’s easier to work with nature than against it.

Sidebar: Bt for mosquito control

Perhaps nowhere has Bt usage had such dramatic effects as in fighting mosquitoes and the

illnesses they carry. Historically, mosquitoes have been implicated as transmitters for

malaria, encephalitis, and dengue fever, but more recently have been recognized as the

carriers of West Nile viruses and many other viruses, pathogens, and parasites. Mosquitoes of

in the genera Aedes, Anopheles, Culex, Psorophora, and Stegomyia cause much human misery

and have high societal costs associated with them.

Bacillus thuringiensis israelensis, or Bti, has been used effectively to kill many species of

mosquitoes within these genera, as well as other biting flies in the Order Diptera worldwide;

this has been demonstrated repeatedly through field studies in Africa, Asia, Australia, Eastern

and Western Europe, India, and North America. Though not registered by the USEPA, B.t.

sphaericus (Bs) also has activity against mosquito larvae, as does B.t.jegathesan. Field tests

have shown significant reductions in both mosquito numbers and associated malarial cases.

Formulations are important with Bt products applied to aquatic systems. Dry preparations

tend to be less successful, as the spores settle to the bottom and are not eaten by larvae,

which tend to be near the surface of the water. Biofilms, fizzy tablets, and slow-release

floating rings are more effective in this regard. The latter two formulations are readily

available, inexpensive, and can be easily handled and applied by volunteers. They should be

used anywhere that standing water – and mosquito larvae – accumulates. Treatments often

need to be repeated to treat subsequent hatchings.

Though some mosquitoes have developed resistance to some Bacillus species, applying these

biopesticides in rotation has overcome resistance. Use of other IPM choices, such as

predatory fish, can help reduce larval numbers. Finally, new strains of Bti and Bs are

constantly being discovered in rice fields, plantations, gardens, and other habitats with

standing water.

Bti has generally been seen to be safe for non-target aquatic organisms, such as dragonflies,

damsel flies, notonectid bugs, fishes, frogs and birds, according to the majority of studies

that have been performed. Conflicting information comes from two studies in Minnesota: one

over 3 years and the second over 6 years. The shorter of the studies reported severe declines

in Diptera species, causing the authors to question the environmental safety of Bti. However,

the longer study found no negative effects on zooplankton or bird populations resulting from

insect decreases. These authors noted that the ecological complexity of wetland food webs

and/or other environmental factors could nullify the impact of reduced insect numbers.

Indeed, the first authors acknowledged that droughty years would cause a similar decline in

insect populations, a completely natural situation from which one would expect the system to


Conventional mosquito treatment has usually consisted of DDT, a highly toxic, broad-spectrum

pesticide whose residues persist throughout food chains decades after their application.

Though banned in the US since 1973, DDT is still legally applied to many regions of the world

where malaria is a problem. Less devastating are the synthetic pyrethroids, which still kill

about 150-200 non-target organisms for each adult mosquito killed. In comparison, Bt

products represent a much gentler approach to mosquito management.

Dr. Linda Chalker-Scott, PhD

Associate Professor and Extension Urban Horticulturist

WSU Puyallup Research and Extension Center

7612 Pioneer Way E

Puyallup, WA 98371

Phone: (253) 445-4542

Email: lindacs@wsu.edu

URL: http://www.puyallup.wsu.edu/~Linda%20Chalker-Scott/

Printable version of Western Spruce Bud Worms (PDF)

Western Spruce Budworms

by D.A. Leatherman, J.W. Brewer and R.E. Stevens 1 (2/09)

Quick Facts...

 Western spruce budworms are the most important tree defoliators in the West.

 Budworm larvae eat the new growth of host trees.

 Douglas-fir is the favored host in Colorado.

 Budworm has a one-year life cycle.

 Budworm control measures usually are conducted in June.

Description and Life Cycle

The western spruce budworm, ChoristoneuraoccidentalisFreeman, is the most widely distributed and destructive forest defoliator in western North America. Several outbreaks have occurred in Colorado, the largest exceeding two million acres. In Colorado, they most commonly infest Douglas-fir and white fir. Occasionally, they also attack Engelmann spruce, blue spruce and subalpine fir.

Western spruce budworm adults (Figure 1) normally are small, mottled, rusty-brown moths, but color can vary from tan to almost black. In Colorado, they are present from late June to early August. After mating, females lay masses of overlapping green eggs on the undersides of needles (Figure 2). The masses consist of 25 to 40 eggs that hatch in about 10 days. The young larvae do not feed but move to crevices under bark scales or lichens where they spin silken shelters called hibernaculae. There they remain dormant throughout the winter.

In late April or May, the larvae migrate to the foliage, where they mine old needles or feed on host tree flowers. In a week or two, they enter developing buds, the habit that gives them their name. As the new needles lengthen, the rapidly growing larvae continue to feed. It is during this stage that most of the damage occurs. They web the new foliage together loosely and feed inside, where they are somewhat protected from predators and other enemies.

In the late larval stages (Figure 3), budworms have brownish heads and brownish-olive bodies. Each body segment has two conspicuous pairs of white spots. About 40 days after feeding begins in the spring, usually about the end of June, the larvae pupate inside feeding webs or on foliage. Adults emerge a week or so later and the cycle is complete. There is one generation per year.

Damage and Associated Impact

Budworms are important because they can eat all the new growth produced by host trees. The new needles are most important in producing food for the tree, so the immediate effect of defoliation is a reduction in growth.

To the homeowner, defoliation mostly means a loss of aesthetic value. As defoliation progresses, both in extent and duration, more significant impacts are likely. The foliage, especially the branch tips, turns brown and dies. Twigs, branches or entire tops of trees may be killed. During long-running outbreaks, three to five years or more, may trees will die. Nonfatal defoliation may also lead to infestation by the Douglas-fir beetle or other bark beetles. In turn, these can kill the tree.


Budworms like forest stands that are dense, dominated by host species of all sizes, surrounded by similar forests, and stressed. Silviculture practices that thin forests, convert them to nonhost species, or limit host species to one size help prevent serious damage. This is the long-term solution to budworm.


Budworm populations usually are held in check by a combination of predators, parasites, adverse climatic conditions, or inadequate food supply. Spiders, insects and a variety of birds are important predators. Adverse weather conditions, particularly sudden freezes in late spring, may kill large numbers of larvae. A major factor in ending long-term outbreaks appears to be starvation from inadequate or nutritionally poor food sources. However, this may not be a factor in urban situations. Cultural practices such as thinning, watering and fertilizing, which promote tree vigor, may help trees better withstand repeated attacks.

Chemical control often is used to protect high-value trees from defoliation and associated damage. The materials listed below are registered for western spruce budworm control and have been used with success in Colorado. They can be applied both from the ground and aerially. In either case, time spraying to occur during the two to three weeks immediately following bud break or flush of new growth. In most years, this occurs about mid-June.

Table 1: insecticides for control of western spruce budworm.


Trade name

Bt (Bacillus thuringiensis)

Dipel, Thuricide, Biobit, Foray (aircraft spraying)



Related Insects

A close relative of western spruce budworm, the so-called pine budworm, Choristoneuralambertianaponderosana(Obraztsov), also is present in this area (See fact sheet 5.567, Ponderosa Pine Budworm). This species attacks pines, especially ponderosa pine, and occasionally causes serious damage to individual trees. However, it is not normally an important defoliator in the urban environment.


Fellin, David G. and Jerald E. Dewey, Western Spruce Budworm. USDA Forest Service, Forest insect and Disease Leaflet 53, 1982.

 Furniss, R. L. and V. M. Carolin. Western Forest Insects. USDA Forest Service Miscellaneous Publication No. 1339, 1977.

1 D.A. Leatherman, Colorado State Forest Service entomologist; J.W. Brewer, Colorado State University former professor, zoology and entomology; and R.E. Stevens, former Rocky Mountain Forest and Range Experiment Station entomologist. 2/99. Reviewed by I. Aguayo, forester, Colorado State Forest Service. 2/09.

Go to top of this page.

Updated Monday, August 29, 2011

CSU Homepage | FileShare | Disclaimer | Equal Opportunity | Privacy Policy | Search CSU | Webmaster | Site Map

Partners | Non-Discrimination Statement | ©2011 Colorado State University


Printable verion of Blueweed (PDF)

Blueweed (Echium vulgare)

Monthly Weed Post March 2011

Identification Blueweed or viper’s bugloss is a member of the Boraginaceae family. It grows as a biennial to short-lived perennial and reproduces by seeds, termed nutlets. Plants overwinter as rosettes. Rosette leaves are simple, entire, lance shaped, 2.5-10 inches long and covered with fine hairs. Funnel-shaped, five-lobed flowers are bright blue, but may also be purple, pink or rarely white. Flowers have five bright red to pink stamens. Mature plants grow one to numerous erect, branching stems that may reach over 3 feet in height. Blueweed may be confused with others plants such as some of the native Penstemon species with blue flowers, which are also funnel-shaped and have five stamens. However, blueweed is distinct due to its brightly colored stamens; short and long hairs that cover the stems and leaves; and the spotted appearance on the stems due to a dark coloring at the base of its long bristly hairs (see photo lower right). Refer to the Extension bulletin (link below) for other look-a-likes and more assistance on blueweed identification.

Impacts While the plant is not considered palatable to livestock, it does contain toxic alkaloids that can cause liver failure when ingested. Blueweed may displace native plants and it is also a known host for several plant diseases, including some viruses spread by aphids and three types of wheat rust.

Habitat This species is typically found in disturbed areas and overgrazed range or pastureland, although it has also been found in well maintained pastures. It thrives in sandy, well-drained soils with low nutrient levels and tolerates dry conditions.

Spread Wind, water, animals and humans all contribute to spread of blueweed. Seeds may be transported long distances as hay and grain contaminants or when they become lodged in vehicles and equipment. Disturbance, especially overgrazing, facilitates blueweed establishment and spread.

Management Priorities Blueweed is a state listed Priority 2A weed in Montana. Small infestations can be managed by hand-pulling or digging, while larger infestations can be treated with herbicides. Early detection of new plants followed by effective action to control them is critical. It has been recorded in 8 counties, predominantly in the northwest part of the state, with the highest number of records in Ravalli County. For more information on blueweed, see “Biology, Ecology and Management of Blueweed (Echium vulgare)” EB0195: http://msuextension.org/publications/AgandNaturalResources/EB0195.pdf

Printable version of Curly Leaf Pond Weed (PDF)

Curlyleaf Pondweed


Monthly Weed Post June 2011

Identification: Curlyleaf pondweed is a submersed aquatic plant. Alternately arranged leaves are stiff, ½-inch wide and 2-3 inches long. Plants begin growth in early spring and flower in late spring to early summer. The inconspicuous, reddish-brown flowers emerge above the surface of the water. Some native Potamogeton species may be mistaken for curlyleaf. In Montana only curlyleaf pondweed has crinkled, undulating leaf margins that resemble lasagna noodles with minute ‘teeth’.

Claspingleaf pondweed and other native pondweeds may look a bit wavy, but an additional characteristic for the native pondweeds are leaf veins that run parallel to the midvein, while curlyleaf pondweed veins branch perpendicularly from the midvein (see inset above).

Impacts: Profuse growth early in the season creates dense mats that inhibit boating and swimming and can shade and inhibit growth of native plants. The massive amounts of vegetative matter die back in late summer, modifying nutrient levels and increasing algal blooms.

Habitat: Plants grow from the shore to depths of 15 feet in ponds, streams, and rivers. Curlyleaf pondweed is able to tolerate a moderate current.

Spread: Curlyleaf pondweed does not typically produce viable seed, and reproduction is primarily by stem fragments and vegetative structures called turions that resemble small pine cones. Turions are produced along the stems just before plants die back in mid-summer. Turions sprout in the autumn and remain alive under the ice and snow, and begin a period of rapid growth in early spring.

Management Priorities: Curlyleaf pondweed is listed as a Priority 1B noxious weed in Montana. It was first reported in Montana in Lake County in 1973 and has since been found in the following counties: Sanders, Ravalli, Deer Lodge, Granite, Madison, Gallatin, Broadwater, Lewis & Clark, Cascade, and Powell. The majority of reports come from Lewis & Clark and Sanders counties, but the plant is likely much more widespread than reported. Prevention is the most important management strategy. Thoroughly wash and carefully inspect all recreational equipment before entering a new body of water (especially boat trailers, propellers and bilge water). Once infested, short-term control of dense mats can be obtained with herbicides and/or mechanical harvesting. For example, a large crew of volunteers raked and bagged an infestation at the East Gallatin Recreation Area in Bozeman, MT (photo at right), improving conditions for swimming, boating and fishing. For more information on curlyleaf pondweed, see the Montana Weed Control Association’s Curlyleaf Pondweed Identification sheet at http://www.mtweed.org/curlyleaf-pondweed/ or the Minnesota Department of Natural Resource’s site at: 

ATTENTION! Have you heard about the Yellow Starthistle Weed Watch Day, August 4, 2011, in Stillwater County? Read more about it at ‘Upcoming Workshops and Events’ on our website: http://www.msuextension.org/invasiveplantsMangold/extensionsub.html

Printable version of Eurasian Watermilfoil (PDF) 

Eurasian Watermilfoil (Myriophyllum spicatum L.)

Monthly Weed Post January 2011

Identification: Eurasian watermilfoil (hereafter referred to as EWM) is a submersed aquatic plant. Leaves are whorled in groups of four and each leaf consists of 14 or more paired leaflets. While flowering may be prolific, germination is rare and most reproduction is asexual from root crown buds and stem fragments. This plant can be difficult to distinguish from two native milfoils. Refer to the Extension bulletin in the link below for more information.

Impacts: EWM forms dense tangled beds that can displace submersed native plant communities, impact recreation, clog agricultural and drinking water supplies, and negatively impact fish and wildlife.

Habitat: EWM colonizes rivers, lakes and other water bodies. It can tolerate moving water, and water currents and wave action facilitate fragmentation, enabling dispersal. Optimum depth ranges from 3 to 13 feet, but it can grow in water up to 24 feet deep if the water is very clear. It was first reported in Montana in Noxon Reservoir in 2007. In 2010 numerous records came from six additional counties (Table 1).

Spread: Plants spread through stem fragmentation. Water recreation (primarily boats and boat trailers) is the predominant vector of long distance dispersal.

Management priorities: EWM is a priority 1B noxious weed in Montana. After prevention, early detection and immediate action to contain and eradicate infestations are the most important management actions for EWM. For more information on identification as well as management options see “Biology, Ecology, and Management of Eurasian Watermilfoil” EB193.

Table 1. Eurasian watermilfoil records submitted to INVADERS Database. http://invader.dbs.umt.edu 



Notes from INVADERS Database



Noxon Reservoir (first confirmed record in Montana)



Cottonwood Channel (upper reaches of Canyon Ferry Reservoir, north of Townsend)



Toston Dam, plants scattered at least 1 mile upstream from dam



Jefferson River 0.5 and 1.5 miles below Williams Bridge Fishing Access



Jefferson River at Drouillard Fishing Access.



Prairie Dog Island, near Buggy and Little Buggy Creek. Some plants were 8-10’ long



Big Dry Arm



Rock Creek Marina



Plant observed floating in the water, upstream from Timber Creek and Bone Trail



First dredge cut below Fort Peck Dam



Fort Peck Marina



Pines Boat Ramp

Please note
: An Invasive Aquatic Plant Management Plan is being developed for the state of Montana. A session at the MWCA Annual Conference on Thursday, January 13th is dedicated to discussing this plan. Please join this session to learn more about the plan and provide constructive feedback.

Printable version of Flowering Rush (PDF)

Flowering Rush (Butomusumbellatus)

Monthly Weed Post November 2011

Identification: Flowering rush is an aquatic species resembling a large sedge, but it belongs to its own family, Butomaceae. Leaves are triangular in cross section (photo at right, top), narrow and twisted toward the leaf tip. Flowering rush is easy to identify when flowering; 20-50 flowers grow in a round cluster that resembles an umbrella. Each flower is ¾ to 1 inch wide, with six light pink to rose-colored petals, nine stamens, and six carpels (photo at right, bottom). The roots are fleshy and rhizomatous. Note: flowering rush does not always flower. On Flathead Lake, it may resemble the native Bristly Sedge, Carexcomosa, a rare species.

Impacts: Flowering rush grows prolifically in irrigation canals, impeding water flow. Some infested canal systems in southern Idaho must be chained every 2-3 years to control flowering rush and increase water availability. Flowering rush also impacts recreational activities by colonizing open waters and interfering with boat propellers, swimming, and fishing. Flowering rush can adversely impact native fish species by forming dense stands in waters previously unvegetated or sparsely vegetated by aquatic plants.

Habitat: Flowering rush grows along lake shores, slow moving waters, irrigation ditches and in wetlands. It typically grows in shallow waters, but has been observed in very clear water up to 20 feet deep in Flathead Lake. When depths are greater than about 10 feet, it modifies its growth form: submersed leaves become limp and ribbon-like.

Spread: Flowering rush has buoyant rhizomes that fragment easily, facilitating long distance dispersal. Ideal conditions for rhizome establishment are shallow, sparsely vegetated or unvegetated silty substrates and water currents less than 2 mph. In Montana flowering rush occurs on Flathead Lake and the upper and lower Flathead River. Populations continue down the Clark Fork River reaching the Clark Fork delta at the head of Lake Pend Oreille (Idaho).

Management Priorities: Flowering rush is listed in Montana as a Priority 1B noxious weed.

Education and prevention of further spread are the main management priorities for flowering rush. Thoroughly wash all recreational equipment and remove any plant parts wrapped around boat propellers and stuck to trailers. Dispose of plant material away from the shores. Research is ongoing to find effective control strategies. For existing infestations, bottom barriers have been effective at suppressing flowering rush (photo at left). Keep a vigilant eye when recreating in Montana waters and report any findings to the Montana Department of Agriculture; Montana Fish, Wildlife and Parks; or your county Extension agent or weed coordinator. For more information on this species, see “Biology, Ecology and Management of Flowering Rush (Butomusumbellatus)”. 

Printable version of Hoary Alyssum (PDF)

Hoary alyssum (Berteroaincana)

Monthly Weed Post May 2011

Identification: Hoary alyssum is an exotic annual to short-lived perennial forb of the Brassicaceae family. Hoary, meaning grayish or aged, refers to the grayish-colored foliage caused by tiny, stellate (star-shaped) hairs that cover the surface (visible with a hand lens). Plants are typically 7-30 inches tall with numerous flowering stems. Leaves are entire, and alternately arranged. Flowers grow in racemes clustered at the stem tips. Each of the four small, white petals has a notch, giving the petal a rabbit-ear shape (inset image at right). Consistent with most Brassicaceae flowers, there are two short outer stamens and four long inner stamens. Hoary alyssum may flower from early spring to late fall given adequate water and light.

Impacts: Toxicity to horses has been reported when green or dried forage is contaminated by more than 30 percent. It can proliferate in forage crops, pastures, and rangelands and rapidly fills in areas disturbed or overgrazed.

Habitat: Hoary alyssum thrives on dry and disturbed ground on soils with poor fertility. It is commonly found growing along roads and trails (below), gravelly stream and lake banks, in lawns, farmyards, and vacant lots. It can also be found in pastures and hayfields. In Montana, it has been reported in 27 counties, with the highest number of reports coming from Gallatin, Jefferson, Madison, and Ravalli Counties.

Spread: Hoary alyssum likely originated in North America as a contaminant of clover and alfalfa seed. Contaminations of forage and lawn seed, as well as contaminated hay, are still considered likely means of long distance seed dispersal. Seed may also disperse long distances on mowers, vehicles, other machinery, and in contaminated soil and gravel. Because the plants are not particularly palatable, it will increase in range and pastureland without proper management

Management Priorities: Hoary alyssum is listed as a Priority 2A noxious weed in Montana. Maintaining healthy stands of vegetation and reseeding after major disturbances are the best ways to prevent establishment. Hand pulling small infestations is effective as long as the root crown is removed (best achieved when the soil is moist). For larger infestations, herbicides are an effective control option, but repeated applications may be necessary to treat plants that emerge throughout the growing season. For hayfields and pastures, methods to improve the health of the existing plant community, such as irrigation or fertilization where available, and proper grazing are recommended. Applying herbicide and reseeding sparse pastures should help to provide long term control of hoary alyssum. For more information see “Biology, Ecology, and Management of Hoary Alyssum” EB0194 

Printable version of Knapweed (PDF)

Knapweed Identification

Monthly Weed Post September 2011

This Weed Post focuses on knapweed identification. More information on impacts, habitat, spread and management priorities can be found in the recently revised “Biology, Ecology and Management of Montana Knapweeds”, available at: http://msuextension.org/publications/AgandNaturalResources/EB0204.pdf

Why focus on identification? There are eight troublesome, non-native knapweed species shown in Figures 1-8 below, and telling them apart can be tricky. Proper identification is the first step towards effective management. Knapweeds on the Montana noxious weed list are shown in Figures 1-4. Figures 5-8 show knapweeds that resemble Montana state-listed species, and we should be aware of them because they are noxious weeds in other northwestern states and have been reported occasionally in Montana.

Figures 1-4. Montana state-listed knapweeds; the first three are priority 2B, and yellow starthistle is priority 1A. (1) Russian knapweed, Acroptilonrepens, formerly Centaurea repens; (2) Spotted knapweed, Centaurea stoebeformerly Centaurea maculosa; (3) Diffuse knapweed, Centaurea diffusa; (4) Yellow starthistle, Centaurea solstitialis.

Figures 5-8. Other non-native knapweeds that may occur in Montana, but are not on the state noxious weed list (northwestern state(s) where noxious). (5) Brown knapweed, C. jacea, (WA); (6) Black knapweed, C. nigra(WA); (7) Meadow knapweed, C. pratensis, (ID, OR, WA); (8) Squarrose knapweed, C. virgata(UT).

Except for yellow starthistle with its bright yellow flowers and long, sharp spines (Figure 4), a careful examination of knapweed bracts is necessary to distinguish among them (see insets in Figures 1-8).

  • Both Russian (Figure 1) and brown (Figure 5) knapweed bracts have no fringes or spines, but a papery translucent edging. Russian knapweed bracts are yellow to green and end in a point, while brown knapweed bracts are brown at the base and flared out rather than pointed.
  • Spotted (Figure 2), black (Figure 6) and meadow (Figure 7) knapweed bracts all have similar fringes, making them difficult to distinguish. The fringes on spotted knapweed are equal to or shorter than the bract width; in contrast, fringes on black and meadow knapweed are longer than the bract width. Fringe color differentiates black (black) and meadow (brown) knapweeds.
  • Both diffuse (Figure 3) and squarrose (Figure 8) knapweed bracts have a short terminal spine. Spines on diffuse are straight and point upwards, and those on squarrose are curved, pointing outward.

Printable version of Reveqitation of Cheat Grass Invested Range Land (PDF)

Revegetation of Cheatgrass-Infested Rangeland: Size Matters!

Monthly Weed Post February 2012

Identification and Biology: Many people are familiar with cheatgrass (Bromus tectorum); we have all picked its seeds out of our socks. This prolific seed producer ranges from 6 to 24 inches tall. Leaf sheaths and blades are covered with soft hairs, and the panicle is 2 to 6 inches long and droops to one side (Fig.1). Each seed has a distinctive awn, 3/8 to 5/8 inch long. Cheatgrass is a facultative winter annual plant; most individuals germinate and emerge in the fall, grow rapidly until winter, and resume growth very early in the spring, though it also emerges in the spring if conditions are right. Plants flower and produce seeds by early summer and then die by mid-summer.

Impacts and Management: Impacts of cheatgrass invasion range from decreasing forage value for livestock and wildlife to altering fire regimes. Preventing soil disturbance and maintaining healthy plant communities are key management strategies for this species. When an infestation occurs, herbicide applications and targeted grazing can be effective methods of control. However, when cheatgrass has dominated an area for a long time, simply controlling it may not be sufficient to restore the perennial plant community. In these cases, revegetation is necessary, and consists of site preparation to control cheatgrass followed by a fall-dormant seeding of perennial species using a rangeland drill or broadcast seeding methods.

Barriers to Restoration: Revegetation of cheatgrass-dominated rangeland often fails. One reason it fails is because cheatgrass and perennial grasses have different life histories: cheatgrass seedlings emerge in the fall and resume growth earlier in the spring relative to perennial grasses. This creates a ‘priority effect’, or a difference in performance due to one species establishing and actively growing by the time the other species emerges. The resulting size difference may result in poor establishment of perennial species because the larger cheatgrass plants take up more resources like soil water and nutrients than do smaller perennial seedlings.

Recent Research: Improving Perennial Seedling Survival: We conducted a greenhouse study to investigate whether allowing the perennial grass bluebunch wheatgrass (Pseudoroegneria spicata) to emerge first would give it a priority effects advantage and increase its competitive ability, and whether modifying nitrogen levels would affect competitive outcomes. To look at these questions, we established three size cohorts of bluebunch; it was either at the 2-leaf or 4-leaf stage when cheatgrass was planted into pots (Fig.2), or the two species were seeded at the same time. We subjected these plants to two nitrogen levels; either a low level (no N added) or a high level (N added to 275 lbs/ac), and looked at the treatments over a range of densities similar to what might occur in the field. We found that larger bluebunch avoided suppression by cheatgrass more effectively, and that it did so regardless of N level. When the two were seeded at the same time, a 10-fold increase in cheatgrass density decreased average bluebunch biomass by 57%. In contrast, when bluebunch had a four-leaf size advantage, the same increase in cheatgrass density only decreased bluebunch biomass by 13%. Larger bluebunch also suppressed cheatgrass more effectively; however, N enrichment decreased bluebunch’s ability to suppress cheatgrass. These results suggest that management practices that encourage perennial grasses to emerge before cheatgrass could improve seedling establishment in revegetation projects. Further, avoiding conditions that lead to N increases, such as soil disturbance, could allow perennial grasses to better suppress cheatgrass.

Printable version of Scotch Broom (PDF)

Scotch Broom


Monthly Weed Post April 2011

Identification: A member of the pea family (Fabaceae), Scotch broom is a perennial deciduous shrub that reproduces by seed. Initially it grows quite rapidly, reaching 8 feet in height within the first two years, and up to 13 feet after 6-10 years. The stems are green when young and become woody as they age. They are angled (square or with edges) and have no spines. Leaves are alternate and trifoliate, or clover-like, except at the branch tips where they are simple. Flowers are bright yellow. The fruit is a flattened pod (resembling a sugar snap pea) up to 2 inches long and contains 5-9 seeds. Immature pods are green, and turn black as they age.

Impacts: Scotch broom can out-compete species for light and nutrients and form dense monospecific stands. It can impact conifer forests and has reduced biomass of juvenile Douglas-fir trees by as much as 96%. As a nitrogen fixer, it can modify nutrient levels. It is also toxic to livestock due to the presence of quinolizidine alkaloids, but it is rarely grazed. Livestock poisonings have been reported in Europe, but are very rare in the United States.

Habitat: Scotch broom prefers areas with mild winters and warm summers, but it can tolerate very cold conditions as well. It prefers a soil pH of less than 6.5, and is rarely found on limestone-derived or calcareous soils. It is typically found in disturbed areas-especially along roadsides and on road cuts, in pastures, open forests, gravel pits, and cultivated fields, but is also known to colonize undisturbed shrub and grass lands and open canopy forests located below 4,000 feet elevation. It is extremely shade tolerant, requiring as little as 10% ambient sunlight for seedling establishment, allowing for germination in shaded areas or under forest canopy.

Spread: In the Pacific Northwest, seed is commonly spread in gravel and by vehicles used for road construction associated with timber harvest. Locally, seeds typically don’t fall more than 3 feet from the parent plant. Ants, which are attracted by a substance exuded by the seed, may disperse seed up to 15 feet or more.

Management Priorities: Scotch broom is listed as a Priority 1B noxious weed in Montana. Because limited populations have been reported only in Sanders and Lincoln Counties, prevention is the top management priority. Learning to identify Scotch broom so it can be detected and eradicated early is critical. Plants don’t reproduce until the second year, but they can then produce up to 30,000 seeds that may last more than 30 years in the soil. For more information on this plant, see “Biology, Ecology and Management of Scotch Broom”, EB 0202 

Printable version of The Knotweed Complex (PDF)

The Knotweed Complex (Polygonum spp.)

Monthly Weed Post February 2011

Identification Species in the knotweed complex are large, rhizomatous, herbaceous perennials varying in height from 5 to 19+ feet tall. They have showy flowers (right) and resemble bamboo with their hollow stems, and knobby nodes with a membranous sheath (inset photo). The complex typically includes Japanese knotweed (Polygonum cuspidatum), giant knotweed (Polygonum sachalinense), Himalayan knotweed (Polygonum polystachyum) and Bohemian knotweed (Polygonum x bohemicum), a hybrid of giant and Japanese knotweed. Leaf shape of Himalayan knotweed is long and narrow, and width is less than half the length. Leaves of the other three are generally heart shaped, and differentiated from each other by veins on the underside of the leaves: Japanese veins have ridges, Bohemian have knobs, and Giant have multicellular hairs. A hand lens is needed to see these differences. Refer to the Extension bulletin in the link below for more information.

Impacts Knotweeds were originally introduced for showy privacy hedges. Due to their aggressive rhizomatous growth, hedges become advancing walls (left). Knotweeds can outcompete existing vegetation to form dense monotypic stands, especially along waterways (below). Rhizomatous growth damages infrastructure and is capable of penetrating through 2” of concrete. Once established, control is extremely difficult.

Habitat Knotweeds are often found in yards and managed landscapes where they were intentionally planted. Escaped plants are commonly found in moist areas such as along riverbanks, canals and lakeshores. However, knotweeds can tolerate a range of moisture conditions and also occur in disturbed areas like utility pathways, strip-mining areas and roadsides.

Spread Dispersal occurs most commonly by rhizome fragments along waterways or in transported soil. Do not spread soil from an area with knotweed to other areas. Rhizome fragments as small as 0.02 lb (7 g) can regenerate to form new plants. Spread by seed is rare.

Management Priorities Giant, Himalayan and Japanese knotweeds are Priority 1B noxious weeds in Montana. Bohemian is the most widespread knotweed in Washington and British Columbia and has been reported in Montana. While plants in the knotweed complex occur in scattered areas across the state, they do not yet line rivers or roadways like in other regions. Prevention must be the number one priority as once established, eradication is extremely difficult. Control options include repeated cutting or hand pulling and herbicides by foliar application or stem injection. For more information on management recommendations, see “Biology, Ecology and Management of The Knotweed Complex (Polygonum spp.),” EB0196. 

Printable version of Western Salsify (PDF)

Western Salsify

by Jane Mangold, MSU Extension Invasive Plant Specialist, and Allison

Lansverk, Research Assistant


known as goatsbeard or yellow salsify, is an exotic plant

of the Asteraceae family that can be weedy in rangelands,

pastures, Conservation Reserve Program (CRP) lands, and

roadsides throughout North America. The name “salsify”

means “a plant that follows the sun,” aptly named because

open flowers point towards the sun and follow it across the

sky, often closing by late morning or early afternoon. The

term “goatsbeard” comes from a reference to the conspicuous

pappus on the flowerheads gone to seed as observed by

the third century B.C. Greek philosopher Theophrastus,

indicating this plant has been associated with people for a

long time. (Terms in bold can be found in the glossary on

page 4.)

Native to Eurasia and northern Africa, western salsify was

commonly used as a food plant in northern Europe in the

Middle Ages and subsequently spread all around the world.

It was brought to North America by early settlers as a food

plant and ornamental around the turn of the 20th century.

Currently, western salsify is widespread across North America.

It has been reported in every state except Alabama, Florida,

Mississippi, and South Carolina; in every Canadian province

except Newfoundland; and in all counties in Montana.

Western salsify can be problematic in rangeland and CRP in

north-central Montana where it has been observed to form

dense stands that replace other vegetation and decrease forage production.


Western salsify has linear, grass-like leaves that clasp the stem

at the base. Prior to bolting and flowering, the leaves can be

readily mistaken for grass (Figure 1). However, they have a

smoother and more rubbery-like feel than grass leaves, have

hairs in the axils, and exude a milky juice when broken. The

yellow, dandelion-like flower heads are born singly on 12 to

40 inch (30 to 100 cm) stems that are swollen and hollow

below the flower head (Figure 2). Ten or more long, narrow

involucral bracts extend beyond the flowers. There are 20

to 120 ligulate flowers per head. The flowerhead matures to

form a three to four inch diameter fluffy sphere comprised

of seeds with long, slender beaks and a white, umbrella-like

pappus that aids wind dispersal (Figure 3). The fluffy sphere

of seeds looks similar to that of a dandelion, only much

larger. Western salsify has a thick, fleshy taproot.

FIGURE 1. Western salsify rosette. FIGURE 2. Western salsify flower. FIGURE 3. Fluffy sphere of western salsify


For More Online MontGuides, Visit www.msuextension.org


MT201113AG New 12/11

Western salsify, also known as goatsbeard, is an exotic plant that can form

dense stands that displace other vegetation and decrease forage production.

This publication will describe how to identify western salsify, explain its

biology and ecology, and discuss management including the results of a

research trial conducted in north-central Montana.


Ecology and Biology

Western salsify is a monocarpic perennial dependent upon seed production to maintain and spread populations. Being monocarpic, the plant dies after seed production. This can happen in its first to fourteenth year (rarely), but usually after two to four years. Seed viability has been measured at 94 percent, and both primary and secondary dormancies have been exhibited by salsify. Secondary dormancy is induced by low oxygen conditions typical of deep burial (one to two inches) or inundation by water. Dry storage releases seeds from secondary dormancy.

Each flower head produces about 20 to 120 seeds of two types; a heavier, darker seed is produced from the outer ring of florets on the flower head, while a lighter seed is produced from the central florets. This difference in seed morphology may result in differences in germination potential and dispersal characteristics. For example, research suggests that smaller seeds from the center florets result in smaller seedlings. However, when growing in competing vegetation, seedling size decreased as seed size increased, whereas when growing in competing vegetation plus plant litter, seedling size increased as seed size increased. Additionally, the dark peripheral seeds, which tend to be larger, have a terminal velocity that is 1.3 times greater than the central seeds, which suggests lower dispersal potential.

Germination peaks have been observed in the fall and the following spring. Over a thirteen month period, all but three percent of a seed crop germinated indicating little contribution to the long-term seed bank. Light is not required for germination, and emergence is not inhibited by a canopy of vegetation or litter. Seedlings quickly gain access to light by the growth of long narrow cotyledons through competing vegetation or litter. Rosettes have an erect growth form (Figure 1) which allows them to colonize intact plant communities. An extensive root system is developed during the vegetative life history stage. Carbohydrates are stored in both the thick roots and in the rosette leaves. The initiation of flowering may be induced by a cold period. When rosettes develop over a prolonged vegetative phase with little flowering, the increase proportionally of rosettes in the population develops a “bud bank” that compensates for the lack of representation in the seed bank.

Flowering occurs in early to mid-June and can extend into September. Only one flower head is produced per stalk, but plants may produce several flowering stems, ranging from one to 14 flowers per plant. Flowers are insect pollinated. One study found an average of 90 seeds produced per plant. Wind-dispersed seeds may travel up to 825 feet (250 m).

Western salsify will grow across a variety of soil types ranging from sandy to clay loam. While it is frequently found in highly disturbed sites, it also occurs in less disturbed areas as well and grows in a wide variety of vegetation zones ranging from arid grasslands to mesic forests. Like other weeds, it can form dense stands that displace other vegetation and decrease forage production and plant diversity. For example, research in British Columbia, Canada, suggested that western salsify reduced the leaf area and shoot-to-root ratio of bluebunch wheatgrass, an important component of native rangeland.

Various parts of western salsify are consumed by wildlife. In Oregon, western salsify was shown to be one of the most important plant foods of blue grouse (Dendragapus obscurus) during the fall. Western salsify, along with four other species, made up 68 percent of the blue grouse diet by weight. Flowering stalks and foliage are utilized by a variety of mammals. For example, pocket gophers (Geomysbursarius) frequently feed on salsify roots. Other mammals such as deer, squirrels, or rabbits may bite off one or more flowering stalks. Mature plants tend to be grazed less frequently.


Very little information exists regarding western salsify control. Research in Canada estimated four years of control using picloram at one pint per acre and one year control using dicamba at two quarts per acre. Herbicides currently labeled for western salsify control include Chaparral® (metsulfuron methyl + aminopyralid) at 3.0 to 3.3 oz/A (ounces per

Other Salsify Species in Montana

Several salsify species grow across North America, and four species in addition to western salsify have been reported in Montana. Those include meadow salsify (T. lamottei; T. pratensis), common salsify (T. porrifolius), Moscow salsify (T. miscellus), and remarkable goatsbeard(T. mirus). Leaves and milky juice of meadow salsify are similar to those of western salsify. The flower is also yellow, but the bracts do not extend beyond the flower head, and the flower stalk is not hollow or swollen beneath it. Common salsify is also similar in appearance to western salsify, but the flower is purple instead of yellow, and the seed pappus is brownish instead of white. Moscow salsify is a hybrid of western and meadow salsify, while remarkable goatsbeard is a hybrid of western and common salsify. The hybrids typically have characteristics intermediate between the two parents. Moscow salsify and remarkable goatsbeard allegedly escaped from the Washington State University garden in Pullman, Washington, prior to the 1950s. Meadow salsify has been reported from 22 Montana counties; common salsify has been reported from eight Montana counties. Moscow salsify has been reported in Flathead, Madison, and Carbon counties, whereas remarkable goatsbeard has been reported in Lake and Judith Basin counties.


acre), Cimarron® Plus or X-tra (chlorsulfuron +

metsulfuron methyl) at 1.25 to 2 oz/A, and Escort®

(metsulfuron methyl) at 1 to 2 oz/A.

While not tremendously problematic, small

infestations of western salsify can be hand-pulled

or dug. Research suggests burying seeds greater

than three inches deep prevents emergence, so

tilling may be effective, but not recommended

unless tilling is followed by seeding of desirable

plants. Western salsify can be a seed contaminant,

so buying weed-free, high quality seed can help

prevent introductions on cropland, pasture and

conservation seedings.

To help develop herbicide management of

western salsify, research trials were conducted in

north-central Montana on CRP lands with varying

degrees of infestation. In spring and early summer

2010, a variety of treatments (Table 1) were tested

at three sites of varying infestation density [low (~1 flowering

plant/m2), medium (~3 plants/m2), and high (~34 plants/m2)].

All herbicide treatments were applied with 0.10 percent

nonionic surfactant (Penetrator®) plus 0.10 percent water

treatment solution (BroncMax®). Glyphosate was a 4-lb

formulation and 2,4-D was an LV-6 formulation. Herbicide

treatments were applied with a CO2 backpack sprayer

delivering about 16 gallons of water per acre at 40 to 42 psi.

Mowing was accomplished once at the bolting/flowering stage

using a standard push mower set to mow to a four to six inch

stubble height. Density and biomass were sampled in early

August for two years (2010 and 2011).

When compared to the no management control,

treatments significantly reduced western salsify flowering

and rosette plants only at the high density site. This suggests

there may be a threshold salsify population density below 34

plants per square meter, below which there is no benefit to

management. Conversely, medium densities of salsify (~three

plants per square meter) may be beneficial for wildlife habitat,

particularly for blue grouse and the closely related sage grouse.

At the high density site in 2010, flowering salsify plants

were only reduced compared to the no treatment control

by treatments 2 and 6 (Figure 4A). Timing of application

appeared to be important, in that treatment during the

rosette stage generally outperformed later applications during

bolting/flowering (e.g. treatment 2 versus treatment 4).

However, by 2011 all herbicide treatments reduced flowering

plant density compared to both the mowing treatment and

the control (Figure 4A). When compared to the control,

all herbicide treatments reduced rosette densities in 2010

(Figures 4B). These results support the idea that herbicides

that target the rosettes, or the bud bank, will effectively reduce

salsify populations in the short term. In addition, all herbicide

treatments reduced the salsify population to a level that may

still provide benefit to wildlife.

TABLE 1. Management treatments and their timing of application (rosette

= 15 May and bolting/flowering = 20 June) to low, medium and high density

salsify infestations in north-central Montana. Treatment 6 had two application

timings: glyphosate plus 2,4-D at rosette stage and dicamba plus 2,4-D,

plusmetsulfuron at bolting/flowering. Numbers in parenthesis following the

chemical name are the chemical rates in ounces product per acre.

Treatment Timing

  1. glyphosate (4) +2,4-D (3) rosette
  2. dicamba (4) + 2,4-D (10) rosette
  3. dicamba (2) + 2,4-D (10) + metsulfuron (1/10) rosette
  4. dicamba (4) + 2,4-D (10) bolting/flowering
  5. dicamba (2) + 2,4-D (10) + metsulfuron (1/10) bolting/flowering
  6. glyphosate (4) +2,4-D (3); rosette;

dicamba (2) + 2,4-D (10) + metsulfuron (1/10) bolting/flowering

  1. mowing bolting/flowering
  2. no management (control)

FIGURE 4. Treatment effect on western salsify flowering plant density (A, left) and rosette density (B, right) across years at a site in

north-central Montana with a high degree of infestation. Treatments are described in Table 1. Lower case letters separate means

across treatments within 2010, while upper case letters separate means across treatments within 2011. ‘*’ indicates where means

differed between 2010 and 2011 within a treatment.





To order additional publications, please contact your county or reservation MSU Extension office, visit our online

catalog at www.msuextension.org/store or e-mail orderpubs@montana.edu

The U.S. Department of Agriculture (USDA), Montana State University and Montana State University Extension prohibit discrimination in all of their programs and activities on

the basis of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital and family status. Issued in furtherance of cooperative

extension work in agriculture and home economics, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Douglas L. Steele, Vice President

of External Relations and Director of Extension, Montana State University, Bozeman, MT 59717.

Copyright © 2011 MSU Extension

We encourage the use of this document for nonprofit educational purposes. This document may be reprinted for nonprofit educational purposes if no endorsement of a commercial

product, service or company is stated or implied, and if appropriate credit is given to the author and MSU Extension. To use these documents in electronic formats, permission

must be sought from the Extension Communications Coordinator, 115 Culbertson Hall, Montana State University, Bozeman MT 59717; E-mail: publications@montana.edu

File under: Agriculture and Natural Resources (Weeds)

New December 2011 300-1211SA

Mowing reduced neither the flowering nor rosette salsify

density compared to the control. From 2010 to 2011 there

was a similar flowering plant density increase in the mowing

and control plots (Figure 4A), and a similar decrease in

rosette densities (Figure 4B). The increase in light from canopy

removal through mowing may have resulted in more robust

rosettes that flowered in 2011. This is supported by the large

increase in the number of flowering plants from 2010 to 2011

in the mowing plots. Therefore, results do not support mowing

as a management recommendation to reduce salsify, which

suggests grazing management may not be effective either.

Perennial grass density and biomass were highest in

treatment 2. Weedy annual grass densities only increased in

treatments 5 and 6. All other treatments had annual grass

densities similar to the control.

The results support a recommendation of four ounces

of dicamba combined with 10 ounces of 2,4-D applied at

the rosette stage (treatment 2, Table 1) for managing salsify

because it provided effective control of western salsify and

resulted in an increase of perennial grasses without stimulating

annual grasses. This study supports management of high

density sites since western salsify flowering plants increased

from 2010 to 2011 in the mowed and non-treated sites,

suggesting continued increase and spread if left untreated.

Treatment differences were not detected at the medium and

low density sites probably because of the patchy distribution of

plants. Broadcast herbicide application to treat western salsify

in such situations may not be necessary, but spot treatment of

dense patches may prevent infestations from worsening.


Beak - A long slender tip or projection

Bolting - When a plant extends a flowering stem

Cotyledon - Embryonic leaf in the seed, often persisting in

the seedling as lowermost leaves or leaf-like structures (two in

dicots, one in monocots)

Involucral bracts - A whorl or series of closely arranged

bracts (reduced leaves) below a flower

Monocarpic perennial - Reproducing in a single bout during

a lifetime, usually dying afterwards

Pappus - Modified calyx (outermost series of flower parts;

sepals) in flowers of the Asteraceae family, consisting of

bristles, scales, awns, or a short crown at tip of achene

Rosette - Cluster of leaves radiating out in all directions from

the stem, usually at base of plant


Clements, D.R., M.K. Upadhyaya, and S.J. Bos. 1999. The

biology of Canadian weeds. 110. Tragopogon dubiusScop.,

Tragopogon pratensis L., and Tragopogon porrifolius L.

Canadian Journal of Plant Science 79:153-163.

Upadhyaya, M.K., M.Q. Qi, N.H. Furness, and R.S. Cranston.

  1. Meadow salsify and western salsify: two rangeland

weeds of British Columbia. Rangelands 15:148-150.


The authors would like to thank USDA-Natural Resources

Conservation Service and USDA-Farm Services Agency for

financial support; John Good, Logan Good, and Randy

Vischer for cooperating on the research trials; and Jim Jacobs,

Jesse Fulbright, and Bill Evans for reviewing an earlier version

of this document.

Common Salsify as an Edible Plant

Although the roots of all the salsify species found

in North America are edible, common salsify is the

species that is widely cultivated as a vegetable. This

plant is often called “vegetable oyster” or “oyster plant,”

referring to the faint oyster-like flavor possessed by

the roots. The parsnip-like roots can be harvested in

spring, but the flavor is reportedly enhanced if roots are

harvested after a freeze in the fall. A botanist from the

16th century described the taste as surpassing that

of carrots or parsnips. The greens may also be eaten

and have a sweet taste. Uses for common salsify range

from soup and salads to a dietetic medicine. The use

of common salsify as a vegetable plant has primarily

occurred in Europe and has declined over time.

Printable version of White Bryony (PDF)

White Bryony (Bryonia alba)

Monthly Weed Post October 2011

White bryony is a poisonous plant with foliage and fruit that closely resembles edible grapes. We hope this Monthly Weed Post will help people recognize white bryony that might be growing in their yard or neighborhood. Identification is especially important for those of you who like to forage or have small children that could mistake white bryony for grapes or other edible fruit.

Identification: White bryony is a non-native perennial herbaceous vine. Leaves are simple, palmate, and broadly toothed. Flowers are greenish white or pale yellow, up to ½ inch in diameter. Berries are initially light green, and change to black when mature (Figure B), closely resembling a Montana native, riverbank grape (Vitisriparia. Figure E). Unlike riverbank grape, white bryony has small white glands or dots on the surface and underside of the leaves (Figure C). White bryony does not have a woody stem like riverbank grape (Figure D).

White bryony (A, B, C) Riverbank grape (D, E, F)

Impacts: Described as the “Kudzu of the West” white bryony grows rapidly, as much as 6” per day. Infestations growing on small trees and shrubs can eventually block all light to the host plant. Dense infestations of white bryony on shrub or tree hosts causes snow to accumulate on the limbs, leading to breakage or loss of branches, which can make the host susceptible to disease and insects. White bryony berries are poisonous. Human fatality has been reported when less than 40 berries were consumed.

Habitat: The plant generally occurs as a climber in trees and fence rows. It was introduced as an ornamental and used primarily in horticultural plantings, so it is commonly found in yards and old homesteads.

Spread: Birds consume the seed and spread it widely. The plant is often found growing beneath places where birds perch such as fencelines, trees, and powerlines.

Management Priorities: White bryony is not listed as a noxious weed in Montana, but it is listed in Idaho. If you find this plant in your neighborhood, we strongly recommend removing it. Digging up the root is the most effective control method and should be done in autumn after the leaves have died back. The roots must be severed 3-4 inches below the soil surface. Watch for new plants or re-growth and repeat root severing as often as necessary. Wear protective gear (gloves, long sleeves, etc.) when handling the plant as it can irritate the skin. Monthly Weed Post October 2011 2

Weed Post Puzzle: Test your knowledge of white bryony












1 – Color of immature white bryony berries

3 - Thinking of making jam or wine from this plant? Think again—40 berries from this plant may be fatal

5 - Both white bryony and grape vines have this feature to help them cling to and climb up structures

7 – White bryony should not be confused with this edible Montana native

9 - Best time of year to sever white bryony roots

10 - White bryony's rapid and aggressive growth rate is similar to this invasive vine of the eastern U.S.

1 - These dots are on both sides of a white bryony leaf, but not riverbank grape leaves

2 - Some birds' favorite roost, white bryony is commonly found beneath these in suburban alleys (two words).

4 - Use these when handling white bryony to avoid skin irritation

5 - Sever the root at least _____ inches below the soil to control white bryony

6 - White bryony leaf shape

8 - Mature color of white bryony berries

Printable version of Whitetop (PDF)

Whitetop (Cardaria spp.)

Monthly Weed Post August 2011

Identification: Globe-podded whitetop(C. pubescens), lenspodwhitetop(C. chalepensis), and heart-podded whitetop(C. draba) are three closely related exotic mustards (Brassicaceae family) often referred to collectively as ‘whitetop.’ All three have small white flowers with four petals, six stamens, and erect stems with oblong to elliptic, gray-green to blue-green leaves. The lower leaves have a short stalk, but upper leaves are sessile, clasp the stem and have lobes (Figure 1A). Seed pods are necessary to distinguish among the three species (Figure 1 B-D). They bloom in late spring to early summer and reproduce by seed and rhizomes. Seeds typically germinate in the fall and overwinter as rosettes. A B C D

Figures 1 A-D. (A) Upper leaves on all three species clasp the stem and have lobes & lower leaves have a short pedicel. Seed pods of: globe-podded white top (B); lenspodwhitetop(C); and heart-podded whitetop (D). Photos by Richard Old, Steve Mattson, J. Peralta and P. Lezama.

Perennial pepperweed (Lepidium latifolium) resembles whitetop but the leaves have no lobes. Additionally, all three whitetop plants are generally not much taller than knee-high (1-1.5’), while perennial pepperweed can reach heights of 6’ and has stems that are woody at the base.

Impacts: Whitetop displaces native plant species, reduces biodiversity, wildlife habitat and forage production, and threatens the cattle and tourism/recreation industries. Whitetop contains glucosinolates which can be toxic to cattle, but the plant is generally considered unpalatable.

Habitat In Montana heart-podded whitetop has been reported in every county except Daniels and Roosevelt, lenspod in 10 counties, and globe-podded in 8 counties. Whitetop is found predominantly in alfalfa, pastures, rangeland, and along roadways. It often grows on moderately moist, alkaline to saline soils, but can tolerate a wide range of soil types and moisture conditions. Whitetop increases with grazing and irrigation.

Spread: Whitetop spreads by seed and rhizomes. Seed has no mechanism for long distance dispersal, but when consumed by livestock, it survives through the digestive tract. Seed also spreads by water (especially irrigation ditches), contaminated hay, and farming equipment.

Management Priorities: Heart-podded whitetop is a priority 2B species in Montana, meaning priorities are containment or eradication where less abundant. All three species are most invasive in agriculture settings, especially irrigated fields. With few or no disturbances, no irrigation, and with competition from perennial species, they are described as relatively easy to control. All control efforts must be persistent, and require at least 2-3 years of monitoring because they can reestablish quickly from rhizomes. For more information, see “Biology, Ecology and Management of Whitetop” EB138.

Printable version of Yellow Starthistle (PDF)

Yellow Starthistle (Centaurea solstitialis)

Monthly Weed Post July 2011

Identification: Yellow starthistle is a facultative winter annual, typically germinating in the fall and overwintering as a rosette, which resembles a dandelion (below left). Plants bolt in early to mid-summer, and may continue flowering until frost. Plants are easiest to recognize when flowering due to the sharp spines on the flower head, up to 1” in length, and the bright yellow color (below middle). Another characteristic to help identify it is the flattened or winged stems (below right).

Impacts: Yellow starthistle is an aggressive colonizer, present on more than 17 million acres in California alone. It reduces wildlife habitat by outcompeting native plants, reduces forage for livestock, and the sharp spines inhibit recreational activities. The plant is toxic to horses, causing the neurological disorder “chewing disease” which can be fatal.

Habitat Yellow starthistle grows on rangelands, pastures, agricultural areas, along highways or roads, railroad tracks, and other transportation or communication lines. It is most common in sunny, disturbed areas. It has been reported in 10 counties in Montana. The most recent reports are from the following counties: Beaverhead (2009, 2 plants), Stillwater (2009, plants scattered over 10 acres), and Gallatin (2010, 1 plant).

Spread: Long distance dispersal is primarily caused by human activities. Seed heads are caught in the undercarriages of vehicles or in road maintenance equipment and transported in contaminated seed or soil. Additionally, birds such as pheasants, quail, and finches feed heavily on yellow starthistle seed providing for long distance dispersal.

Management Priorities: Yellow starthistle is the only Priority 1A noxious weed in Montana. Prevention and EDRR (early detection and rapid response) to eradicate the plant before it establishes are the top priorities for management. Learn how to recognize this plant and call the MT Dept. of Agriculture (406-444-3140) or your county weed coordinator or Extension agent if you find it. For more information on yellow starthistle, see “Yellow Starthistle: Identification, Biology, and Integrated Management”. http://msuextension.org/publications/AgandNaturalResources/MT201101AG.pdf

Want to be more involved in efforts to keep Montana yellow starthistle-free?

We could really use your help! Participate in the “Yellow Starthistle Weed Watch DayAugust 4, 2011 in Stillwater County. The patch discovered near Columbus in 2009 needs a concerted, community-wide effort. Plants were growing where construction vehicles were stored, meaning seed heads may have been transported throughout the area. You’ll be assigned a route to search and your hard work will be rewarded with an afternoon barbeque and a demonstration by Megan Parker of “Working Dogs for Conservation”. Megan trains dogs to detect high priority invasive species. For information, see “Upcoming Workshops and Events” on our website. 

Please register for this event so we’ll know how many burgers to have ready for the grill. A registration form is on the website, or call Stillwater County Weed Coordinator Lindsey Clark at 406-322-1106. Monthly Weed Post July 2011 2

Weed Post Puzzle: Test your knowledge of Yellow Starthistle




2 - The county to be surveyed on the "Yellow Starthistle Weed Watch Day".

3 - Ouch! Get your gloves and shin guards, these nasty YST weapons may be up to 1" long.

7 - A community-wide event on August 4th to search for YST, followed by a bbq and a demonstration with a weed detecting dog.

11 - The person to call if you want to register for the Yellow Starthistle Weed Watch Day over the phone.

12 - A cottony white _____ remains on the YST receptacle after flowers disperse.*

14 - YST plants bloom from summer until _______.

15 - To avoid being a weed vector, check and clean this area frequently to remove seed heads.

1 - An outcome of horses eating YST.

4 - One of two YST seed types that is retained in the seed head longer, sometimes throughout the winter.*

5 - The Montana county with the most recent report of YST.

6 - Yellow starthistle rosettes may resemble this common lawn pest.

8 - Acronym to describe a weed management strategy of finding, reporting and eradicating a weed before it can establish and spread.

9 - A description for stems like YST's that look like they've been flattened in a plant press.

10 - The number of Montana counties that have reported YST.

13 - Priority level for YST in Montana.

Printable version of Yellowflag Iris (PDF)

Yellowflag iris (Iris pseudacorus)

Monthly Weed Post March 2012

Identification: Yellowflag iris, a member of the iris family (Iridaceae), is a perennial, wetland plant growing from stout rhizomes which contain black sap. Plants grow 3 to 5 feet tall with long, linear leaves, 20 to 40 inches long and 0.4 to 1.2 inches wide. Erect flower stalks are round in cross-section and bear several flowers which are similar to common garden irises. Only two species of Iris are known to occur in Montana outside of horticultural plantings: one is yellowflag iris and the other is the native Rocky Mountain iris (Iris missouriensis). The native iris has blue to purple flowers so it is unlikely to be mistaken for yellowflag iris when in bloom. When not in bloom, the two can be distinguished by the leaves or rhizomes. The leaves of Rocky Mountain iris are generally shorter (8 to 16 inches), and the rhizomes of the Rocky Mountain iris lack black sap.

Impacts: Yellowflag iris forms dense monotypic colonies in riparian areas, crowding-out native species. This can alter riparian function and reduce habitat for wildlife, birds, fish and pollinators. In the eastern United States, reduction of native sedges and rushes that support waterfowl is associated with yellowflag iris invasion. Clumps of yellowflag iris can restrict water flow in irrigation and flood control ditches. Yellowflag iris is considered poisonous due to large amounts of glycosides in the leaves and rhizomes.

Habitat: Yellowflag is typically found in shallow waters, but can occur in depths of 2 to 3 feet. Adaptable to full sun or partial shade, it occurs in forested or open wetlands, riparian and floodplain communities, and in swamps. It is often seen growing along the banks of streams, rivers and irrigation ditches. It grows in temperate climates from sea level to 4300 feet in elevation.

Spread: Horticultural trade has spread yellowflag iris throughout the United States. Once established, it reproduces by seed and vegetatively through rhizomes. In a recent survey of 20 sites in Lake County, seed viability averaged 99%. Flooding may transport rhizomes or seeds downstream where they subsequently establish new colonies. Wave action along lake shores may also break-up rhizome clumps and result in establishment of new colonies along the shore.

Management Priorities: In Montana yellowflag iris is listed as a Priority 2A noxious weed, suggesting isolated populations should be contained or eradicated if possible. Yellowflag iris was first reported in Montana in Lake County in 1966, and has been found in Flathead, Missoula, Ravalli, Granite, Sanders and Gallatin Counties. Prevention and early detection are critical for yellowflag iris management. Monitor riparian and wetland areas, particularly near or downstream of known populations. In irrigation ditches where yellowflag iris is present, woven wire screens constructed at irrigation turnouts have been found to limit spread into adjacent ditches and wetlands. For more information on yellowflag iris, see Biology, Ecology and Management of Yellowflag Iris (Iris pseudacorusL.).  Monthly Weed Post March 2012 2

Weed Post Puzzle: Test your knowledge of yellowflag iris



1 - Yellow flag iris belongs to this family

7 - Isn't this plant good for something? Well, herbalists used rhizomes as an emetic and a _______*

8 - Yellowflag iris may form _______ stands, or dense colonies of a single species

9 - An 8% _______ solution applied to leaves just as plants begin to flower has effectively reduced it (check with state agencies for licensing requirements before applying herbicides to wetlands)*

10 - Flowers have three upward pointing petals and three downward pointing _______ that resemble petals

12 - No flowers? Look for this in the rhizomes to determine its yellow flag iris (two words)

13 - Priority level of yellowflag iris in Montana

2 - It's an iris growing in a natural area with blue or purple flowers (two words)

3 - Spread and establishment potential is enhanced by seeds which contain air, allowing them to _____* and disperse longer distances

4 - Large quantities of _______ make yellowflag iris poisonous to livestock

5 - _____ _____ screens constructed in irrigation turnouts have been found to limit or prevent spread into adjacent ditches or wetlands (two words)

6 - Regular __________ of riparian and wetland areas is highly recommended to enable early detection and eradication

9 - The eastern-most county that yellowflag has been reported in Montana

11 - Yellowflag iris was first reported in Montana in this county

Printable version of Montana Knapweeds (PDF)

Montana Knapweeds

Biology, Ecology and Management of

Celestine Duncan, Consultant, Weed Management Services, Helena, MT

Jim Story, Research Professor, retired, MSU Western Ag Research Center, Corvallis, MT

Roger Sheley, former MSU Extension Weed Specialist, Bozeman, MT

revised by Hilary Parkinson, MSU Research Associate, and Jane Mangold, MSU

Exnsion Invasive Plant Specialist

EB0204 May 2011

Ta b l e o f Contents

Plant Biology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

SpeedyWeed ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Ecology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Habitat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Spread and Establishment Potential . . . . . . . 6

Damage Potential . . . . . . . . . . . . . . . . . . . . . . . 7

Origins, Current Status and Distribution . . . . . . . . . . 8

Management Alternatives . . . . . . . . . . . . . . . . . . . 8

Prevention . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Mechanical Control . . . . . . . . . . . . . . . . . . . . .9

Cultural Control . . . . . . . . . . . . . . . . . . . . . . . . .10

Biological Control . . . . . . . . . . . . . . . . . . . . . . .11

Chemical Control . . . . . . . . . . . . . . . . . . . . . . .14

Integrated Weed Management (IWM) . . . . . . . . 16

Additional Resources . . . . . . . . . . . . . . . . . . . . . . 16

References . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .19

Any mention of products in this publication does not constitute a recommendation by Montana State

University Extension. It is a violation of Federal law to use herbicides in a manner inconsistent with their


Copyright © 2011 MSU Extension

The U.S. Department of Agriculture (USDA), Montana State University and Montana

State University Extension prohibit discrimination in all of their programs and

activities on the basis of race, color, national origin, gender, religion, age, disability,

political beliefs, sexual orientation, and marital and family status. Issued in

furtherance of cooperative extension work in agriculture and home economics,

acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of

Agriculture, Douglas L. Steele, Vice President of External Relations and Director

of Extension, Montana State University, Bozeman, MT 59717.


large - spotted knapweed by Marisa Williams, University of Arkansas, Fayetteville, bugwood.org

top inset - diffuse knapweed by Cindy Roche, bugwood.org

bottom inset - Russain knapweed by Steve Dewey, Utah State University, bugwood.org


This publication provides information on identification, biology and management of spotted knapweed

(Centaurea stoebe), diffuse knapweed (Centaurea diffusa), and Russian knapweed (Acroptilonrepens), a

group of closely related noxious weeds that have invaded Montana. These weeds are well adapted to a wide

range of habitats including open forests, rangeland, roadsides, Conservation Reserve Program (CRP) lands,

pastureland and ditch banks. Russian knapweed can also infest cultivated crop and hay land. The knapweeds

threaten long-term productivity of Montana grazing lands and wildlands. These aggressive weeds displace

native species, change plant community structure, degrade or eliminate wildlife habitat, and reduce forage

for livestock. The economic impact to agriculture and wildlands from these weeds is substantial. Successful

management of knapweeds requires the use of integrated weed management strategies.


Spotted knapweed (Centaurea stoebe, formerly C. maculosa*) is a taprooted,

rosette-forming perennial forb that spreads by seed. Stem height

varies from 8 to 50 inches (0.2-1.2 m). The slender stems are manybranched

and have a single flower at the tip of each branch. Flower

color is usually pinkish-purple, but can also be light purple or white

(Figure 1A). Flower heads are surrounded by small leaf-like structures

called bracts (Figure 1B). The bracts are marked with fine vertical streaks

and tipped with a dark comb-like fringe. These bracts give a “spotted”

appearance to the flower head.

Rosette leaves are indented or divided about halfway to the midrib

(Figure 1C). Rosettes initiate growth in mid-spring, plants typically bolt

in early summer and bloom mid-summer to early fall. Individual flower

heads bloom for two to six days before the bracts close. Bracts reopen

after about 20 days, allowing seed dispersal.

* Latin names follow those currently accepted by the Integrated Taxonomic Information System (ITIS).

FIGURE 1. A) Spotted knapweed flower, B) bract,

and C) rosette (photo A by John Cardina, Ohio State

University, bugwood.org; B and C by Steve Dewey).


FIGURE 2. Diffuse knapweed rosette

(photo by Richard Old, XID Services,

bugwood.org), and bract, inset

(photo by Steve Dewey).

Diffuse knapweed (Centaurea diffusa) is a taprooted

annual, biennial or short-lived perennial

forb that reproduces by seed. Diffuse knapweed

typically grows 6 to 24 inches (15-61 cm) tall

and consists of a single main stem divided

into numerous branches about halfway up the

stem, giving it a ball-shaped appearance and

tumbleweed mobility. Each branch produces

a single flower head. Flowers are usually white

(cover, top left), but occasionally light purple.

Bracts on diffuse knapweed have a rigid terminal

spine about . to 1⁄3 inch long with four to five

pairs of shorter lateral spines (Figure 2, inset).

Bracts can have dark-colored tips but lack the

dark fringe present on spotted knapweed. Plants

form rosettes (Figure 2) that resemble spotted

knapweed. Bolting occurs in early summer, and

plants bloom from mid-summer to early fall.

Russian knapweed (Acroptilonrepens, formerly

Centaurea repens) is a rhizomatous, deep-rooted,

long-lived perennial forb that grows about two

feet tall (0.6 m). Stems are thin, stiff and covered

with soft, short hairs. Like spotted knapweed,

flower color is light pink to purple (cover, bottom

left), but two characteristics distinguish Russian knapweed from spotted

knapweed and other similarly colored knapweeds: (1) flower head bracts

of Russian knapweed have light thin hairs, a papery, translucent tip

and are green at the base (Figure 3, inset) and (2) Russian knapweed is

rhizomatous instead of tap-rooted. Rosette leaves are narrow at the base

and widen toward the tip (Figure 3). Shoots emerge in the early spring,

and plants bolt in early summer and flower from mid-summer to early fall.



Spotted knapweed tolerates a wide range of annual precipitation

levels (8 to 80 inches [20.3–203 cm]). It prefers light textured, welldrained

soils, but occurs in a wide range of soil types. In Montana it

grows in open forests (especially after logging or other disturbances),

shrub and grasslands. While it invades disturbed areas more quickly,


FIGURE 3. Russian knapweed rosette

(photo by Joseph Di Tomasco, UC Davis,

bugwood.org), and bract, inset (photo by Steve Dewey).

S p e e d y We e d I D

Spotted, diffuse and Russian knapweeds may be confused with each other as well as other exotic

knapweeds that occur in Montana in limited numbers and that are not currently state-listed noxious

weeds. Following are brief descriptions of other knapweeds that resemble the state-listed species.

Differences in bract texture, color or shape aid in identification.

  • Brown knapweed (Centaurea jacea,) bracts closely resemble

those of Russian knapweed. Both species have a papery translucent

tip and no spines or fringes. However, brown knapweed bracts

are brown, compared to the yellow-green bracts of Russian

knapweed, and brown knapweed is not rhizomatous.

  • Squarrose knapweed (Centaurea virgata) bracts closely

resemble diffuse knapweed, except squarrose bracts are bent

outward compared to diffuse bracts that point upward.

  • Black (Centaurea nigra, A) and meadow knapweed (C. debauxii,
  1. B) may resemble spotted knapweed, but their fringes are longer

than the bracts are wide in contrast to spotted knapweed fringes

which are shorter than the bract width. The fringe on black

knapweed is black; the fringe on meadow knapweed is tan to

brown. The scientific name for meadow knapweed has changed

many times. It may also be referred to as C. pratensis, C. nigrescens,

  1. x moncktonii, C. debeauxiissp. thuillieri, and C. jaceax nigra.




Descriptions adapted from Roche and Roche, 1993.

Knapweed photos: brown by Lee Michels; squarrose by Steve

Dewey; black by Eleanor Sulys; meadow by Cindy Roche.

Illustrations courtesy of Cindy Roche.

it can invade healthy, undisturbed

plant communities as well. Success

increases with disturbance and

soil moisture stress. Steep, south

facing shrub and grasslands are

especially vulnerable. It is common

on roadsides, range and pastureland

(Figure 4) and ditch banks. Spotted

knapweed does not do well in

saturated soils such as irrigated

pastures and can be outcompeted by

healthy grasses at more moist sites.

Diffuse knapweed has similar climatic and soil type preferences to

spotted knapweed and is adapted to a wide range of habitats including

open forests, range and pastureland, roadsides and ditch banks.

Russian knapweed may occur in the habitats described above, but its

tolerance for poorly drained, saline, alkaline soils extends its range to

irrigation ditches, flood plains and river corridors. It is likely to be a pest

in crops and hay fields where its rhizomatous growth makes it difficult

to control. In the north-central part of Montana, it is common in alfalfa

and grain fields in the Missouri River bottomlands.

Spread and Establishment Potential

Spotted knapweed seed production varies from 500 to 4,000 seeds

per plant depending on environmental conditions. Seed longevity is

greater than eight years. While seeds have no specialized appendages

for dispersal, other vectors enable widespread dispersal. Seed heads are

caught in the undercarriage of vehicles enabling long distance dispersal.

Contaminated crop seed, hay, gravel and road fill also contribute to

spread. Wildlife and domestic livestock that consume mature seed heads

excrete viable seed seven to 10 days after consumption, providing seed

dispersal into remote areas. Seed can be spread via rivers and other

waterways, especially when spotted knapweed grows along banks.

Surveys along major Montana highways (Figure 5) found spotted

knapweed is much more abundant in the western part of the state and

declines eastward. Presence is also predicted to decline with distance from roads.

Diffuse knapweed seed production may range from 900 to 1200 seeds

per plant, but can increase to over 18,000 on irrigated sites. Seed


FIGURE 4. Stand of spotted knapweed near Missoula,

Montana (Norman E. Rees, USDA Agricultural Research

Service, bugwood.org).


longevity is estimated to be greater than eight years. Seeds buried 1.2

inches (3 cm) or deeper do not germinate. A flush of seedlings may follow

a disturbance that brings seeds to the surface. Seeds are spread by the

same mechanisms described for spotted knapweed. Additionally, mature

plants break at ground level and tumble in the wind spreading seed.

Russian knapweed seed production is highly variable, but generally lower

than the other knapweeds. Plants along roadsides or on rangelands

average 100 to 300 seeds per plant, but may increase to 1,200 under

optimal conditions. Seed longevity is two to nine years. Russian

knapweed has no appendages for dispersal, and seed is spread by the

same mechanisms as for spotted knapweed. Once established, patches

expand mainly by rhizomatous growth. Mature plants can spread radially

from established plants’ rhizomes and can cover up to 23 feet (7 m)

over two growing seasons. Rhizome fragments created after plowing

or other disturbances can also increase spread. Competitive ability and

spread is highly dependent on the

surrounding plant community.

Rhizomatous grasses can suppress

this plant, but if competing

vegetation is sparse or highly

disturbed, or droughty conditions

prevail, Russian knapweed is highly competitive.

Damage Potential

Knapweeds are associated with

reductions in native plants,

reduced forage yields and degraded

habitats in range, grasslands

and agricultural areas. Based on

estimates from 1996, knapweeds

cost Montana $42 million per year

in direct and indirect costs.

Russian knapweed can cause “chewing disease” in horses, a

neurologic disorder that causes brain lesions and mouth ulcers.

Symptoms of chewing disease include drowsiness, difficulty in eating and

drinking, twitching of the lips, tongue flicking and involuntary chewing

movements. There is no cure and horses die of dehydration or starvation.

Horses will select other forage when available.

FIGURE 5. “Risk” map for spotted knapweed occurrence.

Red signifies high environmental suitability with declining

suitability through orange, yellow, light green and dark

green. This map was generated from presence and

absence data collected along one mile segments for

Montana Department of Transportation maintained

highways and interstates during summers of 2003 and

  1. Data were modeled with general linear regression

with an addition dispersal function away from roads

(Repath et al. 2007).


Spotted knapweed is native to grassland steppes of central Europe and

east to central Russia, Caucasia and western Siberia. Spotted knapweed

was introduced to North America from Eurasia as a contaminant in

alfalfa. It was also introduced through discarded soil used as ship ballast.

Spotted knapweed was first recorded in the Northwest in Victoria,

British Columbia, in 1883 and in Montana in Ravalli County in 1920.

By 1991 the weed had been recorded in every Montana county. Spotted

knapweed is the most widespread knapweed in the state, infesting from

two to five million acres. Spotted, diffuse and Russian knapweeds are

listed as Priority 2B noxious weeds in Montana.

Diffuse knapweed is native to

the grassland steppes of eastern

Europe and Asia Minor. It grows

in the eastern Mediterranean

area, in western Asia, and from

southern Russia to western

Germany. It was first recorded in

North America in Washington in

1907 and in Montana’s Mineral

County in 1951. Presently, 39

Montana counties have reported

the presence of diffuse knapweed

(Figure 6). According to reports from 2003, diffuse knapweed accounts

for less than 1 percent of the total area infested by knapweeds in Montana.

Russian knapweed is native to Mongolia, Russian Turkestan, Iran,

Turkish Armenia and Asia Minor. Seeds of Russian knapweed were

present in alfalfa seed imported from Russian Turkestan beginning in

  1. Once imported, it spread widely by sale of domestically produced

alfalfa seed or hay containing weed seeds. It was first reported in the

Northwest in Yakima County, Washington, in 1922 and in Fergus County,

Montana, in 1934. By 1991 the weed was recorded in every Montana

county and infests an estimated 51,000 acres.



Prevention, early detection and rapid response are the keys to preventing

the spread of knapweeds onto non-infested range and pasture lands.

Human activities are believed to be one of the largest contributors to


FIGURE 6. Counties in Montana where diffuse knapweed

has been reported (INVADERS Database System, http://invader.dbs.umt.edu).


the spread of knapweed. Vehicles have

been shown to pick up seeds when

driven on unpaved roads and off-road

even under dry conditions. Such seeds

have been recorded to travel over 160

miles under dry conditions with seed

dropping off much more quickly under

wet conditions. Therefore, a vehicle

driven through a spotted knapweed

patch has the potential to spread seed

hundreds of miles. Avoid driving through

infestations, especially when flowering and shortly thereafter and wash

the undercarriage of vehicles that have been in weed-infested areas.

Construction equipment, fill dirt and gravel (Figure 7) are common

sources of weed seed. Where construction, road building, maintenance

or some other major disturbance is planned, monitor regularly for several

years (bimonthly the first year and monthly for the following three to four

years). Do not drive, walk or trail livestock through weed-infested areas.

Purchase only certified weed-seed free seed and hay.

Proper grazing management is essential to maintain competitive

desired plants, which slow knapweed encroachment. To minimize

weed invasion, grazing systems should alter the season of use, rotate or

combine livestock types and pastures to allow grazed plants to recover

before being regrazed, and promote litter accumulation. On severely

degraded, knapweed-infested rangelands, herbicide treatments should

be combined with revegetation and rested for two to three years to allow

seeded species to establish.

Mechanical Control

Hand pulling: Persistent and careful hand pulling can control spotted and

diffuse knapweed. Since regrowth can occur from crowns, the entire

crown portion of the plant must be removed. Plants can be pulled most

effectively when the soil is moist. If plants are flowering they must be

bagged and disposed of in a manner to prevent seed dispersal. While

this control method is effective on single plants or relatively small

infestations, it is not economically or physically feasible on large, wellestablished

knapweed infestations. Hand pulling is not an effective

treatment for established Russian knapweed patches because the plant

rapidly resprouts from rhizomes.

Mowing: There has been limited research and mixed results on long-term

effects of mowing knapweeds. Mowing can prevent seed production

FIGURE 7. Knapweed seed can be transported by

movement of gravel and other fill material (photo by Duncan).

and reduce carbohydrate reserves. It is typically most effective where the

surrounding plant community contains healthy perennial grasses that

will respond to mowing with renewed growth. By contrast, if the existing

plant community is dominated by forbs or annual grasses, mowing

may simply open the plant community, reducing competition from

surrounding plants, thereby increasing knapweed density.

For spotted knapweed, a Montana study found fall mowing in the

flowering or seed producing stage for three consecutive years reduced adult

plant density by about 85 percent at two locations. However, mowing is

not recommended where biocontrols are well established and serve as the

primary control strategy. Mowing at the recommended time (flowering or

seed producing stage) will destroy insect larvae deposited in flower heads.

In some cases, herbicide efficacy at low application rates may increase

when combined with mowing. For example, mowing at the late bud stage

followed by an application of clopyralid + 2,4-D (CurtailR [1 quart per

acre]) to fall regrowth provided better control than the herbicides applied alone.

Cultivation: Cultivation to depths of 7 inches (18 cm) or more will control

spotted and diffuse knapweed. However, even under intensive cultivation,

weeds will regenerate from seeds remaining in soil. Cultivation will

increase rate of spread and establishment of Russian knapweed since

root sections broken during cultivation will form new plants. Cultivation,

in combination with reseeding competitive perennial grasses, may

minimize reinvasion of the knapweeds.

Burning: A single, low-intensity fire does not control spotted, diffuse

or Russian knapweeds and instead may increase cover and density.

Additionally, it creates open areas which facilitate establishment and

spread of the knapweeds. However, a controlled burn followed by

herbicide may increase effectiveness of herbicide by stimulating and

exposing new knapweed growth prior to herbicide application.

Cultural Control

In areas where desirable plant species are absent, long-term control of

knapweeds is unlikely without revegetation. Successful establishment of

seeded species has been shown to inhibit reinvasion of knapweeds. For

example, at sites in western Montana where intermediate wheatgrass

(Thinopyrum intermedium) was seeded 15 years earlier, spotted knapweed

biomass was reduced by 93 percent. Successful establishment took time and

may have been aided by the presence of well-established biocontrol agents.



For dense infestations, herbicide applications are usually necessary

to reduce competition, providing time for seeded species to establish.

Common approaches include a spring or early summer herbicide

application followed by a dormant seeding in late fall; or a fall herbicide

application and spring seeding. If the site can be cultivated, another

option is to till and seed grasses in the late fall. Both grass and knapweed

seedlings will emerge the following spring as long as there is adequate

moisture. Knapweed seedlings can be controlled with reduced rates

of 2,4-D, clopyralid (TranslineR), triclopyr + clopyralid (RedeemR) or

clopyralid + 2,4-D (CurtailR) once seeded grasses have established.

These broad-leaf herbicides would not be appropriate if forbs or shrubs

are included in the seed mix. In order to make revegetation more costeffective,

a one-pass system or ‘single-entry’ approach can also be used.

In this case, a boom sprayer can be fitted to a no-till drill or other seeding

implement and the seeding and herbicide are applied simultaneously

during late fall. This must be conducted late enough in the fall to ensure

no seeded species germinate before winter. Revegetation guidelines for

Western Montana: Considering Invasive Weeds (see link under Additional

Resources) provides more information on implementing a revegetation program.

For Russian knapweed, a single herbicide treatment followed by

reseeding with rhizomatous grasses can provide long term control and

avoid annual reapplication of herbicide. In Wyoming, clopyralid + 2,4-D

followed by seeding with streambank wheatgrass (Elymus lanceolatus)

controlled 66 to 93 percent of the knapweed two years after treatment.

By contrast, herbicide alone provided only 7 percent control two years

after application, and glyphosate (RoundupR) applied alone increased

Russian knapweed growth compared to no herbicide. In another study,

a single application of clopyralid + 2,4-D followed by seeding western

wheatgrass (Pascopyrumsmithii) effectively controlled Russian knapweed.

Biological Control

Insects -

Spotted and diffuse knapweed: Thirteen insects have been introduced

into Montana for biological control of spotted and diffuse knapweed

(Table 1, page 12). Most of the insects attack both plant species, but

some have a preferred host. Insects that have been particularly effective

on spotted knapweed in Montana include the root feeding weevil

(Cyphocleonusachates), two seed-head feeding weevils (Larinusminutus

and L. obtusus), and the seed-head feeding fly (Urophoraaffinis). Reports

released in 2010 found C. achatescan reduce plant densities by 77 to

99 percent. The root weevil in combination with the seed head insects

has reduced seed production by 94 percent in some places. The root

moth (Agapetazoegana) has also contributed to the reduction of spotted

knapweed in several locations in Montana.

For diffuse knapweed, the root beetle (Sphenopterajugoslavica) and

the flower weevil (L. minutus) have done particularly well, especially near

Helena, Montana. Larinusminutushas two sites of attack: larvae feed

on the seeds, and adults damage leaves of bolting plants. In Colorado

grassland where numerous biocontrols were released, L. minutusappeared

responsible for most of the reductions in diffuse knapweed.

Table 1. Status of insects released in Montana for spotted, diffuse and Russian knapweed.

Scientific Name Insect Type

Plant Part


Date Released Status

Spotted and diffuse knapweed

(s) feeds primarily on spotted, (d) feeds primarily on diffuse

Agapetazoegana(s) Moth Root 1984 Established1

BangasternusfaustiWeevil Flower head 1992 Unknown

Chaetorelliaacrolophi(s) Fly Flower head 1992 Established2

Cyphocleonusachates(s) Weevil Root 1988 Established1

Larinusminutus(d) Weevil Flower head 1991 Established1

Larinusobtusus(s) Weevil Flower head 1992 Established2

Metzneriapaucipunctella(s) Moth Flower head 1980 Established2

Pelochristamedullana(d) Moth Root 1984 Established3

PteroloncheinspersaMoth Root 1988 Unknown

Sphenopterajugoslavica(d) Beetle Root 1983 Established2

Terelliavirens(s) Fly Flower head 1992 Established3

UrophoraaffinisFly Flower head 1973 Established1

UrophoraquadrifasciataFly Flower head 1980 Established1

Russian knapweed

AulacideaacroptilonicaWasp Stem 2009 Established3

JaapiellaivannikoviFly Stem 2009 Established3

MesoanguineapicridisNematode Root 1990 Established3

1 Widely established or established in moderate numbers at numerous sites

2 Established in moderate numbers at several sites

3 Established in very small numbers


FIGURE 8. A) Sheep grazing knapweed,

background, in contrast to ungrazed spotted

knapweed, foreground, B) Lamb consuming

spotted knapweed stems (photo A by Montana

Sheep Institute, B by Gary Mathews).

Other insects listed for spotted and diffuse knapweed in Table 1

generally have not proven as effective. Before releasing any biological

controls, investigate environmental conditions at the site (particularly

climate) and select biocontrols that will do well in those conditions.

For information on preferred habitats of biocontrol agents, see the

online publication Biology and Biological Control of Knapweeds, listed under

Additional Resources.

Russian knapweed: The nematode Mesoanguinapicridismay persist

if conditions are just right, but it has failed to adequately establish

at most locations in Montana. Recent approval and release of two

new insects that target stems hold promise to be more effective on

Russian knapweed: the fly Jaapiellaivannikoviand the nematode Aulacidea


Grazing -

Cattle, sheep and goats will graze spotted

knapweed at low to moderate levels. Although

rosettes of first year knapweed plants are

nutritious and edible, they are typically not

grazed by cattle. Mature spotted knapweed

plants are fibrous and coarse, which make

them less desirable. Cow-calf pairs have been

trained to eat spotted knapweed with some

success. Under a short-duration grazing

strategy with cattle in western Montana,

spotted knapweed seedlings and rosettes

decreased, but bare ground increased

and litter decreased. Any procedures that

increase bare ground on rangeland are

not recommended unless integrated with revegetation.

Sheep grazing can be used to reduce

spotted knapweed seed production (Figure 8). If grazing occurs at the

bolting stage an additional grazing period is recommended, but if grazing

occurs at the late-bud to early flower or full-flower stage, a single grazing

period can reduce viable seed production by nearly 100 percent based

on studies in Montana. Animals that have grazed knapweed beyond the

bolting stage need to be quarantined for seven to 10 days before moving to

non-infested pastures in order to prevent seed transport in animal waste.




Combining herbicides with sheep grazing can also effectively control

some knapweeds. The herbicides can be used to control mature,

unpalatable plants and sheep will selectively remove knapweed rosettes

as they re-emerge. Research in Montana found that spring application

of 2,4-D followed by grazing with sheep was better than either treatment

alone at reducing spotted knapweed cover and biomass. Goats are also

recommended to reduce seed production.

Chemical Control

Selective herbicides provide good control of the knapweeds and are often

the most cost-effective treatment for small or new infestations (Table

2). In cases where desirable remnant vegetation still exists, persistent

spot spraying over two to three years may be enough to release the

desirable plants from competition (Figure 9). For denser infestations

where desirable vegetation is nearly absent, herbicide treatments are most

effective when combined with revegetation or other strategies to enhance

the competitive ability of desirable forage species.

Spotted and diffuse knapweed: Each herbicide has special characteristics

that make it useful in specific situations. Always consult and carefully

read labels before applying herbicides. Picloram provides from two to

seven years of control depending on site conditions and is one of the

most cost-effective herbicides. In a Montana study, picloram provided

better long term control of spotted knapweed and increased grass

biomass compared to clopyralid. However, clopyralid applied at the

bolting stage was as effective as picloram at one of two sites and provided

50 percent reduction in density at the second site. Due to the long soil

residual time of picloram, clopyralid may be a better alternative for more

sensitive areas, especially those with higher forb diversity.

Aminopyralid (MilestoneR) is a relatively new herbicide and has been

highly effective on knapweeds. It has been shown to be as effective as

picloram, and the lower use rates pose less risk to the environment. Like

clopyralid, it has fewer impacts on non-target plants. In field trials at 10

locations spanning four states, only 14 of 68 desired forb species were

moderately susceptible or susceptible to aminopyralid applications at 5

to 7 oz/acre.

A limited number of studies have investigated the compatibility of

herbicides with biocontrols and results are mixed. For the root feeding

  1. zoeganaand C. achates, late spring applications of 2,4-D, or clopyralid

were preferred over fall applications

which can substantially reduce

larval numbers. However, the number of spotted knapweed seed heads

impacted by Urophora species was not different between plots sprayed


FIGURE 9. Left, dense knapweed along trail in Bear Trap Canyon, Madison County, Montana, in fall

  1. Right, the same site in fall 2003 with abundant grasses and near absence of knapweed. Treatment

included spot-spraying in late May and again in late July to early August (when the plants began to flower)

with 1 quart/A picloram (TordonR 22K) + 1 quart/A 2,4-D (photos courtesy of the BLM Dillon Field office

who organized and implemented this weed control program).

Table 2. Herbicides, rates and application times for control of knapweeds.

Spotted or Diffuse Russian


1-2 lb ae/acre. Apply at early stage of bolting.

4-8 lb ae/acre. Apply at early stage of bolting.



5-7 fl oz/acre. Apply from rosette to

the bolting stages or in the fall.

5-7 fl oz/acre. Apply from early bud

to flowering and to dormant plants in the fall.


(TranslineR or


1⁄3-1 pint/acre. Apply after majority

of basal leaves have emerged up to

bud stage or fall regrowth. See label

for site specifics.

0.25-0.5 lb ae/acre (0.66-1.33

pints/acre). Apply up to bud stage.

See label for site specifics.

Clopyralid + 2,4-D


2-3 quarts/acre (higher rate for

dense patches or poor growing

conditions). Apply after rosettes

emerge but before bolting.

3-4 quarts/acre. Apply at the early

bud to mid-flowering stage or on fall regrowth.


(Tordon 22KR)

1-2 pints/acre. Apply from rosette

to mid-bolting stage or to fall regrowth.

2-4 pints/acre. Apply during active

growth from bud to mid-flowering

or to fall regrowth.

Triclopyr +


(Redeem R&PR)

1.5-2 pints/acre. Apply from rosette

to early flower or to fall regrowth.

Optimum time is mid-bolt.

3- 4 pints/acre. Apply from bud to

mid-flower stage or fall regrowth.


with picloram (Tordon) or 2,4-D compared to non-sprayed plots. In

general, herbicide applications are not recommended in the first couple

of years following release of biocontrols.

Russian knapweed: Rhizomatous growth of Russian knapweed can

make it particularly difficult to control with herbicides. Except for 2,4-

D, optimal timing for herbicide application on Russian knapweed is

generally later compared to the other knapweeds (early bud to flowering

compared to rosettes to bolting stages). Combining herbicides with

revegetation is strongly recommended to provide long term control.


Successful management of knapweeds requires the use of integrated

weed management strategies. This includes combining strategies to

prevent the movement of these weeds, containing existing infestations,

and integrating control methods to reduce weed infestations to tolerable

levels. The goal of a management program should be to develop healthy

plant communities that are invasion resistant and meet land-use

objectives. Preventing weed seed spread onto adjacent land is the most

cost-effective management strategy. The following practices will reduce

or eliminate knapweed seed dispersal and establishment:

- Learn to recognize knapweeds and report new occurrences.

- Eradicate small patches of knapweeds before they have a chance to spread.

- Refrain from driving vehicles through infestations and wash vehicles in

a designated area before travelling into non-infested areas.

- Purchase and transport only certified noxious, weed-seed free forage.

- Minimize soil disturbance on range and other non-crop lands.

- Use IWM to contain large knapweed infestations.

- Seed desirable perennial grass species on areas disturbed by

construction, mining or other activities.

- Support local weed management programs.


Goodwin, K. and R. Sheley. 2003. Revegetation Guidelines for Western

Montana: Considering Invasive Weeds. Extension Bulletin 170. http://




Benz L.J., K.G. Beck, T.D. Whitson, and D.W. Koch. 1999. Reclaiming

Russian knapweed infested rangeland. Journal of Range Management.

52(4): 351-356.

Benzel, K., T. Mosley, and J. Mosley. 2009. Defoliation timing effects on

spotted knapweed seed production and viability. Rangeland Ecology and Management. 62(6): 550-556.

Bottoms, R.M. and T.D. Whitson. 1998. A systems approach for management

of Russian knapweed (Centaurea repens). Weed Technology. 12:363-366.

Brown, M., C.A. Duncan and M.B. Halstvedt. 1999. Spotted knapweed

management with integrated methods. Proceedings Western Society of Weed Science. 52: 68-70.

Coombs, E., J. Clark, G. Piper and A. Cofrancesco, eds. 2004. Biological

control of invasive plants in the United States. Oregon State University Press,Corvallis, Oregon.

Corn, J.G., J.M. Story and L.J. White. 2009. Comparison of larval

development and overwintering stages of the spotted knapweed biological control

agents Agapetazoegana(Lepidoptera: Tortricidae) and Cyphocleonus

achates(Coleoptera: Curculionidae) in Montana versus eastern Europe.

Environmental Entomology. 38(4): 971-976.

Duncan, C.L. and J.K. Clark, eds. Invasive plants of range and wildlands and

their environmental, economic, and societal impacts. Weed Science Society of America, 2005.

Halstvedt, M., D. Cummings, T. Almquist, L. Samuel, R. Lym, G. Beck, R.

Becker, C. Duncan and P. Rice. Fall 2010. Native shrub and forb tolerance

to Milestone® herbicide. Techline Newsletter.

Lacey, J.R., C.B. Marlow and J.R. Lane. 1989. Influence of spotted knapweed

on runoff and sediment yield. Weed Technology. 3: 627-631.

Laufenberg, S.M., R.L. Sheley, J.S. Jacobs and J. Borkowski. 2005.

Herbicide effects on density and biomass of Russian Knapweed (Acroptilon

repens) and associated plant species. Weed Technology. 19(1): 62-72.

Lesica, P. 1991. The effect of the introduced weed, Centaurea stoebe, on

Arabisfecunda, a threatened Montana endemic. Montana Natural

Heritage Program, State Library, Helena, Montana.


Mangold, J.M., C.L. Poulsen and M.F. Carpinelli. 2007. Revegetating

Russian knapweed (Acroptilonrepens) infestations using morphologically

diverse species and seedbed preparation. Rangeland Ecology and Management. 60(4): 378-385.

Panter, K.E. 1991. Neurotoxicity of the knapweeds (Centaurea spp.) in horses.

In: Noxious Range Weeds. L.F. James, J.O. Evans, M.H. Ralphs, R.D.

Child (eds.). Westview Press, Boulder, Colorado. pp. 316-324.

Perry, L.G., C. Johnson, E.R. Alford, J.M. Vivanco and M.W. Paschke.

  1. Screening of grassland plants for restoration after spotted knapweed

invasion. Restoration Ecology. 13(4): 725-735).

Repath, C.F., L.H. Rew and F.L. Dougher. 2007. Inventory and probability

of occurrence maps for state listed noxious weed species. Technical Report

submitted to Montana Department of Transportation.

Rew, L. and F. Pollnac. April 2010. Seed dispersal by vehicles. News from

Center for Invasive Plant Management. http://www.weedcenter.org/


Rice, P., M.D. Bendunah and C. Carlson. 1992. Plant community

diversity after herbicide control of spotted knapweed. USDA Forest Service

Intermountain Research Station Paper INT 460.

Rinella, M., J.Jacobs and R. Sheley. 2001. Spotted knapweed response to

season and frequency of mowing. Journal of Range Management. (54):


Rinella, M.J., J.M. Mangold, E.K. Espeland, R.L. Sheley and J.S. Jacobs.

  1. Long-term effects of introducing desired plants into invaded grasslands.

Ecological Applications, in review.

Roche, C.T. and B.F Roche. 1993. Identification of knapweeds and starthistles

in the Pacific Northwest. Pacific Northwest Extension Bulletin 432.

Washington State University Extension.

Seastedt, T.R., N. Gregory and D. Buckner. 2003. Effects of biocontrol insects

on diffuse knapweed (Centaurea diffusa) in a Colorado grassland. Weed Science. 51: 237-245.

Sheley, R.L., B.E. Olson and L.L. Larson. 1997. Effect of weed seed rate and

grass defoliation level on diffuse knapweed. Journal of Range Management.



Sheley, R.L., J.S. Jacobs and M.F. Carpinelli. 1998. Distribution, biology,

and management of diffuse (Centaurea diffusa) and spotted knapweed (Centaurea maculosa). Weed Tech. 12:353-362.

Sheley, R.L., J.S. Jacobs and J.M. Martin. 2004. Integrating 2,4-D and

sheep grazing to rehabilitate spotted knapweed infestations. Journal of Range Management. 57: 371-375.

Sheley, R.L., C.A. Duncan, M.B. Halstvedt and J.S. Jacobs. 1999. Spotted

knapweed and grass response to herbicide treatments. Journal of Range Management. 53(2): 176-182.

Stannard, M. 2004. Basic biology, distribution and vegetative suppression of

four knapweed species. USDA Natural Resource Conservation Service.

Technical Note 18. http://www.plantmaterials.nrcs.usda.gov/pubs/idpmstn5594.pdf

Story, J.M., W.R. Good, L.J. White, and L. Smith. 2000. Effects of the

interaction of the biocontrol agent, Agapetazoegana L. (Lepidoptera:

Cochylidae), and grass competition on spotted knapweed. Biological Control.

17: 182-190.

Thompson, M.J. 1996. Winter foraging response of elk to spotted knapweed

removal. Northwest Science. Vol. 70(1): 10-19.

Winston, R., M. Schwarzlander, C. Randall, and R. Reardon. 2010.

Biology and Biological Control of Knapweeds. USDA Forest Service

Publication FHTET-2010-1. Morgantown, West Virginia. 149p.

Zouhar, K.L. 2001. Acroptilonrepens. 2001. Centaurea diffusa. 2001.

Centaurea maculosa. (three separate documents). In: Fire Effects

Information System [Online]. U.S. Department of Agriculture, Forest

Service, Rocky Mountain Research Station, Fire Sciences Laboratory

(Producer). http://www.fs.fed.us/database/feis/


Publication of this bulletin was made possible with a grant from the

Montana Department of Agriculture Noxious Weed Trust Fund. The

authors would like to thank Monica Pokorny for reviewing this updated

edition and Susan Anderegg for layout and graphic design.


Printable version of Oxeye Daisy (PDF)

Oxeye Daisy

Leucanthemum vulgare Lam.

Synonym = Chrysanthemum leucanthemumL.

PNW 579

Oxeye daisy is a showy perennial herb in the Asteraceae family that was introduced from Europe, most likely as a medicinal herb to treat asthma, whooping cough, and other coughs. Some people enjoy the young leaves in salads. Oxeye daisy is still sold as an herb and as an ornamental by itself and in mixes. Other common names include white daisy, marguerite, field daisy, aspen daisy, poor-land flower, and moon-penny. Oxeye daisy occurs in 17 Idaho counties, 20 Oregon counties, and 40 Washington counties. It is a noxious weed in Washington, and several Idaho counties have added

oxeye daisy to their county noxious weed lists. It is illegal to sell oxeye daisy seeds or plants where it is designated as

noxious. A related species, Shasta daisy (Chrysanthemummaximum), looks very similar and is a better choice for beautifying the landscape. Oxeye daisy prefers upland meadows and pastures but can be found in landscapes, along

roadways, and in fields, rangelands, and waste areas. Once established, it competes against grasses, reducing forage

production. It also exposes soil in the fall making the infested area vulnerable to erosion and other aggressive weeds.

Management practices discussed in this bulletin focus on pasture, rangeland, and roadside infestations.

A Pacific Northwest Extension Publication University of Idaho • Oregon State University • Washington State University

Oxeye daisy flower head.

Mature oxeye daisy

plant. Oxeye daisy looks

similar to the Shasta

daisy (Chrysanthemum maximum).


Author—Steven Hines, Timothy S. Prather, and Sandra Robins

Oxeye daisy rosette.


Oxeye daisy is an herbaceous perennial with rhizomes and adventitious roots. Plants grow 1 to 3 feet in height. Stems and leaves are smooth to sparsely hairy. Basal leaves are spatula-shaped to round and occur on long stalks that are 2 to 5 inches long. The leaf margins are toothed to more or less pinnately lobed. Leaves progressively decrease in size upward on the stem. The upper leaves clasp the stem in an alternate arrangement. The upper leaves are narrowly oblong with toothed to shallowly lobed margins. Flower heads are usually solitary and grow at the ends of the branches. Flowers are showy and daisy-like, with 20 to 30 white ray flowers and numerous yellow disk flowers. Flower heads average 1 to 2.2 inches in diameter. The petals are slightly notched at the tip, and the floral bracts are green with dark brown margins.

The fruit is a round achene, brown to black in color, 1/16 of an inch long, with 8 to 10 ridges down the sides and no pappus. One flower head can contain up to 200 seeds.

Biology and Ecology

Oxeye daisy plants flower June through August. A healthy plant may produce up to 26,000 seeds. The seeds generally germinate in the fall in Idaho, Washington, and Oregon but may germinate throughout the growing season. Dryer fall conditions will delay germination until spring, but the seed does not have a dormancy period. Oxeye daisy seeds maintain viability, and in one study 82 percent of the seed germinated after 6 years and 1 percent germinated after 39 years. Oxeye daisy spreads mainly by seeds, but it also spreads effectively by the rhizomes. Oxeye daisy competes aggressively, especially under continuous grazing pressure. High seed production allows oxeye daisy to quickly take over a pasture or meadow, especially if management allows exposure of bare soil, which is where seeds are more likely to germinate.

Cattle preferably graze other plants when kept in a pasture at low stocking rates, reducing plant competition with

oxeye daisy and allowing it to get an even better hold in the pasture. Ungrazed meadows are susceptible to invasion because the branched rhizomes and strong adventitious roots allow the plant to fully utilize any open space.


Mechanical control

Mowing should be timed to the onset of flowering. Plants may flower more than once, and subsequent mowings also

should be timed to the onset of flowering. Hand weeding of small populations can be effective, especially in moist soil

where more of the root system can be removed by digging. Repeated hand weeding likely will be required because roots

remaining may sprout, forming new plants, and seedlings will continue to emerge because the seeds remain viable for many years.


Horses, sheep, and goats readily consume oxeye daisy, but cattle usually avoid it. Effective grazing programs should include short-duration, high-intensity grazing with cattle prior to flower production followed, if possible, by grazing

with goats or sheep to consume remaining oxeye daisy plants. Grazing will suppress established populations; however,

seeds and rhizomes will replace any oxeye daisy vegetation removed by animals. Oxeye daisy may alter the taste of milk

from dairy cows that have consumed it.

Competitive plants

Perennial bromes, both native and introduced, are competitive with oxeye daisy as are timothy, orchardgrass, tall fescue,

and most native and introduced wheatgrasses. Stimulating grass competition with fertilizer has been shown to increase forage production by 500 percent and hinder oxeye daisy growth. Pastures and meadows with established infestations of oxeye daisy are often nitrogen deficient. In pasture settings, fertilization according to a soil test may be required after control of oxeye daisy to improve growth of grasses and increase their competitive ability. Fertilization timing can be either (1) late spring after a spring herbicide application or (2) early fall to midspring after herbicide application during the previous spring or summer.

Control with herbicides

Several broadleaf herbicides registered for use in pasture are effective against oxeye daisy beginning when leaves are visible in the spring until flowering. Weedy hawkweeds are associated with oxeye daisy, often growing within the same fields, and herbicides mimicking natural plant hormones effective on hawkweeds are also effective on oxeye daisy. Adjuvants should be used according to the specific herbicide label; there are no special adjuvant requirements for oxeye daisy. Herbicides that disrupt plant enzyme production that are effective on members of the aster family are also effective on oxeye daisy. Herbicide recommendations change, often yearly, so please use the guidelines for herbicide use found in the annually revised PacificNorthwest Weed ManagementHandbook available in print or online at http://ag.ippc.orst.edu/pnw/weeds.

Biological control

No biological control agents have been introduced for oxeye daisy control.


Oxeye daisy is well established in the Pacific Northwest. Forage production can be reduced by oxeye daisy competition. Goats and sheep readily eat oxeye daisy, but cattle require high-intensity, shortduration grazing to set back oxeye daisy. Oxeye daisy is susceptible to many herbicides used for pasture and rangeland weed control. Maintaining competitive forages will deter expansion of oxeye daisy populations. Management will require long-term diligence since seed longevity is longer than 6 years.


The Authors—Steven Hines, Extension Educator in Lincoln County, University of

Idaho Extension; Timothy S. Prather, Extension Weed Specialist, University of

Idaho Department of Plant, Soil, and Entomological Sciences, Moscow; and Sandra

Robins, Lambert Erickson Weed Diagnostic Laboratory Taxonomist, University of

Idaho Department of Plant, Soil and Entomological Sciences, Moscow.

Pacific Northwest extension publications are produced cooperatively by the three Pacific Northwest land-grant universities: Washington State

University, Oregon State University, and the University of Idaho. Similar crops, climate, and topography create a natural geographic unit that

crosses state lines. Since 1949, the PNW program has published more than 550 titles, preventing duplication of effort, broadening the availability

of faculty specialists, and substantially reducing costs for the participating states.

Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by University of Idaho Extension, the Oregon

State University Extension Service, Washington State University Extension, and the U.S. Department of Agriculture cooperating.

The three participating extension services offer educational programs, activities, and materials without regard to race, color, religion, national

origin, gender, age, disability, or status as a Vietnam-era veteran as required by state and federal laws. University of Idaho Extension, Oregon

State University Extension Service, and Washington State University Extension are Equal Opportunity Employers.

Published May 2005 © 2005 by University of Idaho $2.50

Oxeye daisy infests open meadows and pastures.

Yard and Garden

Printable version of Composting Article (PDF)


Beware of herbicide contaminated compost

Patricia McGlynn, PhD

Montana State University Agriculture Extension Agent

May 3, 2011


A problem that is becoming an increasing concern is herbicide damage on vegetable plants in backyard gardens. Many homeowners are adding composted manure to their gardens to improve the health of their soil. Compost potentially adds beneficial nutrients and micorrhizal fungus. When the manure has been contaminated by herbicides, it can prove deadly to the vegetable crop.

Stronger herbicides are being used to control noxious weeds in lawns, roadsides and hay fields. A number of these herbicides are exhibiting a long residual in both living and dead plant material. The herbicide will stay active, even though it has passed through the digestive tract of an animal and has been in a compost pile for up to three years, according to the Montana Dept of Agriculture. At a rate of only one part per billion, the herbicides picloram, clopyralid and aminopyralid will damage vegetables and landscape ornamentals.

It is extremely important to know where your manure compost comes from and what the animal has been eating. Certified weed free hay is good for preventing the spread of noxious weeds into our natural areas, but not good for your garden. Many of these hay fields have been sprayed with herbicides to control weeds and this will end up passing through the horses. Cattle can consume herbicides by grazing along treated roadways and fence lines. There was an unfortunate contamination of an organic vegetable farm in the Bitterroot last summer, when a livestock producer unknowingly purchased contaminated hay and fed it to his cattle. An organic farmer bought the manure and spread it on her fields. It will be years before these fields will be able to produce vegetables again.

If you are using chemicals, such as Milestone, to control weeds in your lawn or roadways, follow the instructions on the label. It will tell you how long the residual is and not to compost this material. Homeowners need to be careful adding grass clippings to the garden or compost pile that may have had herbicide treatments. If in doubt, do not use lawn clippings.

In the Flathead Extension office, we received over two dozen plant samples that exhibited herbicide damage last year. A percentage of the symptoms were attributed to overspray and the rest were from contaminated compost. The trade names of the herbicides with long residuals are:

 Picloram - sold as Tordon, Access, Surmount, Grazon, and Pathway.

 Clopyralid - sold as Curtail, Confront, Clopyr AG, Lontrel, Stinger, Millennium Ultra, Millenium Ultra Plus, Reclaim, Redeem, Transline.

 Aminopyralid - sold as Milestone, Forefront, Pharaoh, Banish.

The garden plants most sensitive to these herbicides are:

 Legume family - including lupines, peas, beans and clover.

Compositae family - including daisy, aster, sunflower and lettuces.

 Nightshade family - including tomatoes, potatoes, peppers and eggplants.

Umbelliferae family - including carrots.

 Many other vegetables and flowers.

Sensitive plants that are exposed to these herbicides develop cupped or fern like leaves and twisted stems. The herbicides are growth inhibitors and affect the development of leaves and flowers. The theory behind these products is that they are safer for people or pets.

According to state researchers, the best way to test your compost is this bioassay method.

  1. Thoroughly mix 1-2 parts manure, compost or soil with 1 part commercial potting soil in a clean bucket. Prepare enough to fill three 4-inch pots.
  2. Fill another three clean pots solely with commercial potting soil. These will be the untreated comparisons.
  3. Place each of the pots in a separate saucer to prevent water from one pot reaching another.
  4. Water the pots and leave to stand for 24 hours.
  5. Plant each pot with three pea or bean seeds.
  6. Observe subsequent growth for four-week period and note any ill effects in the pots containing the possibly contaminated mix, such as cupped leaves, fern like growth on new shoots or twisted stems. These symptoms may indicate picloram, clopyralid or aminopyralid residue in the manure, compost or soil. Signs of other kinds of damage will most likely indicate other issues such as damping off or bacteria-infected soil, etc.

This message is not meant to discourage anyone from using composted manure. It is important that you know where your compost comes from. Once contaminated with an herbicide it can be years before you can grow certain crops in that area.

Happy Spring and Happy Gardening.

Printable version of Frost Free Days Chart-MSU Creston Research Station (PDF)

Frost free period at the Northwestern Agricultural Research Center from 1980 - 2011













June 4


Sept. 24




May 5


Sept. 24




May 30


Sept. 15




May 15


Sept. 6




June 2


Sept. 13




May 13


Sept. 7




May 16


Sept. 7




May 22


Sept. 17




May 3


Sept. 12




May 21


Sept. 9




May 10


Oct. 6




May 27


Sept. 19




May 17


Aug. 24




May 4


Sept. 13




April 30


Sept. 12




May 27


Sept. 21




May 21


Sept. 23




May 21


Oct. 8




May 19


Oct. 5




June 7


Sept. 12




June 1


Sept. 22




May 20


Sept. 29




May 23


Sept. 21




May 20


Sept. 30




May 14


Oct. 1




May 24


Sept. 24




May 15


Sept. 17




May 7


Sept. 14




May 10


Sept. 14




May 2


Oct. 6




May 22


Sept 23




May 18


Sept 29



Median Date

for 1980-2011

May 19


September 24




Printable version of Ground Squirrels (PDF)





Leonard R. Askham

Professor Emeritus

Department of Horticulture and Landscape Architecture

Washington State University Pullman, Washington 99164-6414

Damage Prevention and

Control Methods


Limited usefulness.

Cultural Methods

Flood irrigation, forage removal, crop rotation, and summer fallow may reduce populations and limit spread.


None are registered.


Zinc phosphide.



Note: Not all toxicants are registered for use in every state. Check registration labels for limitations within each state.


Aluminum phosphide.

Gas cartridge.


Box traps.

Burrow-entrance traps.

Leghold traps.


Limited usefulness.


Cooperative Extension Division

Institute of Agriculture and Natural Resources

University of Nebraska - Lincoln

United States Department of Agriculture

Animal and Plant Health Inspection Service

Animal Damage Control

Great Plains Agricultural Council Wildlife Committee Identification

The Franklin ground squirrel (Spermophilus franklinii, Fig. 1) is a rather drab grayish brown. Black speckling gives a spotted or barred effect. Head and body average 10 inches (25.4 cm) with a 5- to 6-inch (12.7- to 15.2-cm) tail. Adults weigh from 10 to 25 ounces (280 to 700 g). The Richardson ground squirrel (S. richardson) is smaller and lighter colored than the Franklin. Some are dappled on the back. The squirrel’s body measures about 8 inches (20.3 1. cm) with a tail of from 2 to 4 inches (5 to 10 cm). Adults weigh from 11 to 18 ounces (308 to 504 g). The Columbian ground squirrel (S. columbianus) is easily distinguished from others in its range by its distinctive coloration. Reddish brown (rufous) fur is quite evident on the nose, forelegs, and hindquarters. The head and body measure 10 to 12 inches (25.4 to 30.5 cm) in length with a 3- to 5-inch (7.6- to 12.7-cm) tail. An average adult weighs more than 16 ounces (454 g). The Washington ground squirrel (S. washingtoni) has a small smoky-gray flecked body with dappled whitish spots. The tail is short with a blackish tip. This squirrel is similar to Townsend and Belding squirrels except the latter have no spots. Head and body are about 6 to 7 inches long (15.2 to 18 cm); the tail 1.3 to 2.5 inches long (3.4 to 6.4 cm); and adults weigh 6 to 10 ounces (168 to 280 g). The Townsend ground squirrel’s (S. townsendi) head and body range in length from 5.5 to 7 inches (14 to 18 cm). It has a short bicolored tail about 1.3 to 2.3 inches (3 to 6 cm) long, and weighs approximately 6 to 9 ounces (168 to 252 g). The body is smoky-gray washed with a pinkish-buff. The belly and flanks are whitish. Other species not described here because they cause few economic problems are Idaho (S. brunneus), Uinta (S. armatus), Mexican (S. mexicanus), Spotted (S. spilosoma), Mohave (S. mohavensis), and roundtail (S. tereticaudus) ground squirrels.


Ground squirrels are common throughout the western two-thirds of the North American continent. Most are common to areas of open sagebrush and grasslands and are often found in and around dryland grain fields, meadows, hay land, and irrigated pastures. Details of each species range, which overlap occasionally, are shown in figures 2 and 3.

Food Habits

Ground squirrels eat a wide variety of food. Most prefer succulent green vegetation (grasses, forbs, and even brush) when available, switching to dry foods, such as seeds, later in the year. The relatively high nutrient and oil content of the seeds aids in thedeposition of fat necessary for hibernation. Most store large quantities of food in burrow caches. Some species, like the Franklin, eat a greater amount of animal matter, including groundnesting bird eggs. Insects and other animal tissue may comprise up to onefourth of their diet.

General Biology, Reproduction, and Behavior

Ground squirrels construct and live in extensive underground burrows, sometimes up to 6 feet (2 m) deep, with many entrances. They also use and improve on the abandoned burrows of other mammals such as prairie dogs and pocket gophers. Most return to their nests of dried vegetation within the burrows at night, during the warmest part of summer days, and when they are threatened by predators, such as snakes, coyotes, foxes, weasels, badgers, and raptors. The squirrels generally enter their burrows to estivate, escaping the late summer heat. They hibernate during the coldest part of the winter. Males usually become active above ground 1 to 2 weeks before the females in the spring, sometimes as early as late February or early March. A few may be active above ground throughout the year. Breeding takes place immediately after emergence. The young are born after a 4- to 5-week gestation period with 2 to 10 young per litter. Generally only 1 litter is produced each year. Densities of the ground squirrel populations can range from 2 to 20 or more per acre (5 to 50/ha).

Damage and Damage Identification

High populations of ground squirrels may pose a serious pest problem. The squirrels compete with livestock for forage; destroy food crops, golf courses, and lawns; and can be reservoirs for diseases such as plague. Their burrow systems have been known to weaken and collapse ditch banks andcanals, undermine foundations, and alter irrigation systems. The mounds of soil excavated from their burrows not only cover and kill vegetation, but damage haying machinery. In addition, some ground squirrels prey on the eggs and young of ground-nesting birds or climb trees in the spring to feed on new shoots and buds in orchards.

Legal Status

Ground squirrels generally are unprotected. However, species associated with them, such as black-footed ferrets, weasels, wolves, eagles, and other carnivores may be protected. Local laws as well as specific label restrictions should be consulted before initiating lethal control measures.

Damage Prevention and Control Methods Exclusion

Exclusion is impractical in most cases because ground squirrels are able to dig under or climb over most simple barriers. Structures truly able to exclude them are prohibitively expensive for most situations. Sheet metal collars are sometimes used around tree trunks to prevent damage to the base of the trees or to keep animals from climbing trees to eat fruit or nut crops.

Cultural Methods/Habitat Modification

Flood irrigation of hay and pasture lands and frequent tillage of other crops discourage ground squirrels somewhat. Squirrels, however, usually adapt by building the major part of their burrows at the margins of fields, where they have access to the crop. During the early part of the season they begin foraging from the existing burrow system into the field until their comfort escape zone is exceeded. When this zone is exceeded and as the litters mature in the colony, tunnels will be extended into the feeding area. Late in the summer or fall, tillage will destroy these tunnels but will not disturb or destroy the original system at the edge of the field. Some research has been conducted on the effect of tall vegetation on ground squirrel populations and movements. The data, while sketchy, indicate that the squirrels may move out of tall vegetation stands to more open grass fields. The addition of raptor (hawk, owl, and kestrel) nest boxes and perches around the field border or throughout the colony may reduce colony growth, but is not a reliable damage control method.


Zinc phosphide and anticoagulants are currently registered for ground squirrel control. Since pesticide registrations vary from state to state, check with your local extension, USDA-APHISAnimal Damage Control, or state department of agriculture for use limitations. Additional restrictions may be in effect for areas where endangered species have been identified. Zinc phosphide has been used for several years to control ground squirrels. It is a single-dose toxicant which, when used properly, can result in mortality rates as high as 85% to 90%. If, however, the targeted animals do not consume enough bait for mortality to occur, they become sick, associate their illness with the food source they have just consumed, and are reluctant to return to the bait. This is called “bait shyness.” Repeated baiting with the same bait formulations is generally unsuccessful, particularly when tried during the same year. Prebaiting may increase bait acceptance with treated grain baits. Prebaiting means exposing squirrels to untreated grain bait several days before using toxic grain. Conditioning the squirrels to eating this new food improves the likelihood of their eating a lethal dose of toxic grain. Prebaiting often improves bait acceptance and, therefore, control. The major disadvantage is the cost of labor and materials for prebaiting. Zinc phosphide is classified as a Restricted Use Pesticide and as such, can only be purchased or used with proper certification from the state. Certification information can be obtained from your local Cooperative Extension or state department of agriculture office. Zinc phosphide can be absorbed in small amounts through the skin. Rubber gloves should be worn when handling the bait. Use only fresh bait. Spoiled or contaminated baits will not be eaten by ground squirrels. Old bait may not be sufficiently toxic to be effective. If zinc phosphide baits are more than a few months old they should not be used, particularly if they have not been stored in air-tight, sealed containers, because they decompose with humidity in the air. Chlorophacinone and diphacinone are two anticoagulant baits that have been registered in some states for ground squirrel control and have been found to be quite effective. Both are formulated under a number of trade names. Death will occur within 4 to 9 days if a continual supply of the bait is consumed. If baiting is interrupted or a sufficient amount is not maintained during the control period, the toxic effects of the chemicals wear off and the animal will recover. Baiting should not begin until the entire population is active, 2 to 3 weeks after the first adults appear. If a portion of the population is in hibernation or estivation, only the active animals will be affected. Bait selection should be based on the animal’s feeding habits, time of year, and crop type. Ground squirrel feeding habits vary with the time of year. Grain baits may be more acceptable during the spring when the amount of green vegetation is limited. Pelletized baits using alfalfa or grass as a major constituent may be preferred later in the season. It is important to test the acceptance of a bait before a formal baiting program begins. Place clean (untreated) grains by several active burrows. Use only grains acceptable to the animals as a bait carrier. If none of the grains are consumed, the same procedure can be repeated for pelletized baits. Several formulations may need to be tried before an acceptable bait is selected. If control with one bait is unsuccessful, rebaiting with another toxicant may produce the desired results. This is particularly important when zinc phosphide is used. Follow-up treatments with an anticoagulant will often control the remaining animals. Bait placement is critical. Bait should be scattered adjacent to each active burrow in the amount and manner specified on the label. It should not be placed in the burrow, because it will either be covered with soil or pushed out of the hole by the squirrels. Ground squirrels are accustomed to foraging above ground for their food and are suspicious of anything placed in their tunnel systems. All active burrows must be baited. Incomplete coverage of the colony will result in poor control success. Where broadcast applications are not allowed, baits can be placed in spillproof containers. Old tires have been extensively used in the past but are bulky, heavy, and time-consuming to cut apart and move. Furthermore, bait can easily be pushed out by the animals and the tires can ruin a good sickle bar or header if not removed from a field before harvest. Corrugated plastic drain pipe of different diameters cut into 18- to 24-inch (46- to 61-cm) lengths provide an inexpensive, light-weight, and easy-to-use alternative. Bait stations should be placed in the field at about 50-foot (15-m) intervals a week or so before treatments are to begin. Once the animals use the stations frequently, baiting can begin. Not all bait stations will be used by the squirrels at the same time or with the same frequency. Each station should be checked every 24 hours and consumed or contaminated baits replaced until feeding stops. When the desired level of control has been achieved, the bait stations should be removed from the field and the old bait returned to the original container or properly disposed.


Fumigants are best suited to small acreages of light squirrel infestations. Most are only effective in tight, compact, moist soils over 60o F (15o C). The gas dissipates too rapidly in loose dry soils to be effective in any extensive burrow system. Ground squirrel burrow systems are often complex with several openings and numerous interconnecting tunnels. The cost of using gas cartridges may be more than eight times the cost of using toxic baits. Fumigants registered for ground squirrel control include aluminum phosphide and gas cartridges. Cartridges may contain several combustible ingredients. When using aluminum phosphide, place tablets at multiple entrances at the same time. Insert the tablets as far back into the burrows as possible. Water may be added to the soil to improve activity. Never allow aluminum phosphide to come into direct contact with water, because the two together can be explosive. Crumpled paper should be placed in the hole to prevent the fumigant from being pushed out of the hole by the animals or being covered by loose soil. Plug the burrow opening with soil to form an air-tight seal. Monitor the area for escaping gas and plug holes as needed. When using gas cartridges, punch five or six holes in one end of each gas cartridge and loosen the contents for more complete combustion before use. Insert and light a fuse. Gently slide the cartridge, fuse end first, as far back into the burrow opening as possible and immediately seal the hole with soil. Do not cover or smother the cartridge. Follow all label instructions. Phosphine gas is toxic to all forms of animal life. Inhalation can produce a sensation of pressure in the chest, dizziness, nausea, vomiting, and a rapid onset of stupor. Affected people or animals should be exposed to fresh air and receive immediate medical attention. Never carry a container of aluminum phosphide in an enclosed vehicle.


Traps are best suited for removal of small populations of ground squirrels where other control methods are unsatisfactory or undesirable. Jaw traps (No. 1 or No. 0), box or cage traps, and burrow entrance traps may be used. Place leghold traps where squirrels will travel over them when entering and leaving their burrows. Conceal the trap by placing it in a shallow excavation and covering it with 1/8 to 1/4 inch (0.3 to 0.6 cm) of soil. Be certain that there is no soil beneath the trap pan to impede its action. No bait is necessary. Box or cage traps may be set in any areas frequented by ground squirrels. Place them solidly on the ground so that they will not tip or rock when the squirrel enters. Never place the trap directly over a hole or on a mound. Cover the floor of the trap with soil and bait it with fresh fruit, vegetables, greens, peanut butter, or grain. Experiment to find the best bait or combination of baits for your area and time of year. Wire the door of the trap open for 2 to 3 days and replenish the bait daily to help overcome the squirrel’s trap shyness and increase trapping success. Burrow entrance traps may also be useful. See Thirteen-lined Ground Squirrels for a description of this type of trap.


Shooting may provide relief from ground squirrel depredation where very small colonies are under constant shooting pressure. It is, however, an expensive and time-consuming practice. Hunting licenses may be required in some states.

Other Methods

Gas exploding devices for controlling burrowing rodents have not proven to be effective. Propane/oxygen mixtures injected for 45 seconds and then ignited only reduced the population by about 40%. Vacuum devices that suck rodents out of their burrows are currently being developed and tested. No reliable data, however, exist at this time to confirm or deny their efficacy.

Economics of Damage and Control

Very little is known about the economic consequences of ground squirrels foraging in agriculture. A single pair and their offspring can remove about 1/4 acre (0.1 ha) of wheat or alfalfa during one season. Water lost from one canal can flood thousands of acres or cause irrigation failures. The crop loss and cost of repair can be very expensive. Prevention, by incorporating a rodent management plan into the total operation of an enterprise, far outweighs the cost of added management practices.


Figure 1 from Schwartz and Schwartz (1981).

Figures 2 and 3 adapted from Burt and Grossenheider (1976) by David Thornhill. Some of the material included in this draft was written by C. Ray Record in the 1983 edition of Prevention and Control of Wildlife Damage.

For Additional Information

Albert, S. W., and C.R. Record. 1982. Efficacy and cost of four rodenticides for controlling Columbian ground squirrel in western Montana. Great Plains Wildl. Damage Control Workshop. 5:218-230. Andelt, W. F., and T. M. Race. 1991. Managing Wyoming (Richardson’s) ground squirrels in Colorado. Coop. Ext. Bull. 6.505, Colorado State Univ. 3 pp. Askham, L. R. 1985. Effectiveness of two anticoagulant rodenticides (chlorophacinone and bromadiolone) for Columbian ground squirrel (Spermophiluscolumbianus) control in eastern Washington. Crop Protect. 4(3):365-371. Askham, L. R. 1990. Effect of artificial perches and nests in attracting raptors to orchards. Proc. Vertebr. Pest. Conf. 14:144-148.Askham, L. R., and R. M. Poché. 1992. Biodeterioration of cholorphacinone in voles, hawks and an owl. Mammallia 56(1):145-150. Burt, W. H., and R. P. Grossenheider. 1976. A field guide to the mammals, 3d ed. Houghton Mifflin Co., Boston. 289 pp. Edge, W. D., and S. L. Olson-Edge. 1990. A comparison of three traps for removal of Columbian ground squirrels. Proc. Vertebr. Pest Conf. 14:104-106. Fagerstone, K. A. 1988. The annual cycle of Wyoming ground squirrels in Colorado. J. Mamm. 69:678-687. Lewis, S. R., and J. M. O’Brien. 1990. Survey of rodent and rabbit damage to alfalfa hay in Nevada. Proc. Vertebr. Pest Conf. 14:116-119. Matschke, G. H., and K. A. Fagerstone. 1982. Population reduction of Richardson’s ground squirrels with zinc phosphide. J. Wildl. Manage. 46:671-677.Matschke, G. H., M. P. Marsh, and D. L. Otis. Efficacy of zinc phosphide broadcast baiting for controlling Richardson’s ground squirrels on rangeland. J. Range. Manage. 36:504-506. Pfeifer, S. 1980. Aerial predation of Wyoming ground squirrels. J. Mamm. 61:371-372. Schmutz, J. K., and D. J. Hungle. 1989. Populations of ferruginous and Swainson’s hawks increase in synchrony with ground squirrels. Can. J. Zool. 67:2596-2601. Schwartz, C. W., and E. R. Schwartz. 1981. The wild mammals of Missouri, rev. ed. Univ. Missouri Press, Columbia. 356 pp. Sullins, M., and D. Sullivan. 1992. Observations of a gas exploding device for controlling burrowing rodents. Proc. Vertebr. Pest Conf. 15:308-311. Tomich, P. Q. 1992. Ground squirrels. Pages 192-208 in J. A. Chapman and G. A. Feldhamer. eds. Wild mammals of North America. The Johns Hopkins Univ. Press., Baltimore, Maryland. Wobeser, G. A., and F. A. Weighton. 1979. A simple burrow entrance live trap for ground squirrels. J. Wildl. Manage. 43:571-572.


Scott E. Hygnstrom

Robert M. Timm

Gary E. Larson

Printable version of Home Garden Soil Testing MontGuide (PDF)

Home Garden Soil Testing & Fertilizer Guidelines

by Courtney Pariera Dinkins, Research Associate; Clain Jones, Extension Soil Fertility Specialist/Assistant Professor; and Kathrin Olson-Rutz, Research Associate, Department of Land Resources and Environmental Sciences

For More Online MontGuides, Visit www.msuextension.org

Soil testing and interpreting your soil test results are useful for developing fertilizer rates specific to your garden.

MT200705AG Revised 5/10

THIS GUIDE PROVIDES HOME GARDENERS AND Extension agents the tools to better understand and interpret soil test reports. This understanding should help the reader accurately determine fertilizer rates and the need for soil amendments, such as compost. The data in soil test reports are only worthwhile if the tested soil sample accurately represents the sampled garden; therefore, a summary of sampling methods is provided.

Soil Testing Versus Standard Fertilizer Rates

Due to time and the cost of soil analysis ($20-$50) compared to the cost of fertilizer for a small yard area, many gardeners do not soil test but instead use standard fertilizer rates (Table 1, page 2) which are often given on fertilizer bags. If you are using standard fertilizer rates and your plants appear healthy, we recommend continuing your current fertilizer regimen and soil sample only if you wish to reduce the risk of, or diagnose, a potential nutrient deficiency or toxicity. If you have been using standard fertilizer rates and your plants are not thriving or producing well, soil testing may be the only way to determine if your garden has abnormal levels of nutrients. Although it is often thought that ‘more is better’, gardens can have excessive nutrient levels due to high inputs of compost and/or fertilizer. Excessive levels of fertilizer are not only a waste of money, but can be harmful to your plants and the environment.

Please see the Montana Master Gardener Handbook for more information on standard fertilizer types and amounts for gardens, lawns, shrubs and trees. The web address and ordering information for all Extension documents referenced in this MontGuide are listed at the back of this publication.

Soil Sampling

To obtain meaningful and accurate soil test results, it is important that you correctly collect soil samples from multiple locations within your yard and garden. A minimum of ten samples should be collected and mixed from your garden, or from each 1,000 square feet (sq ft) of lawn to obtain a representative sample. Be sure to remove any mulch or lawn thatch before collecting your soil samples. If there is a visual or textural difference from one side of your garden or lawn to the other, submit separate samples. Samples may be submitted moist or dry. If you decide to soil sample in mid-summer or fall, it is best to wait at least two months after fertilization to give the fertilizer a chance to dissolve, disperse and be used by plants.

Soil samples are best collected using hand probes or augers (Figure 1). Unless it is the only option, you should avoid shovels and spades because it is difficult to obtain the same amount of soil from each depth and location with these tools, possibly biasing results. Hand augers are useful, especially when sampling at different depths. Many Extension offices have hand probes or augers and may either lend you the tools or assist you in soil sampling. An alternative tool to collect a 0 to 6 inch soil sample is a bulb planter (available at most gardening stores). Tools should be cleaned between each garden or area sampled and stored away from fertilizers to prevent contamination.

Sampling Depth and Time

For home gardens, lawns and trees, soil samples are generally a 6 inch deep core from the soil surface. In some cases, soil samples may also be taken below the 6 inch depth. Because nitrogen (N, in the form of nitrate-N), sulfate-sulfur (sulfate-S) and chloride (Cl) are very soluble and can more readily move down into the soil than other nutrients, deeper soil samples can be collected and analyzed for these nutrients. Figure 1. Soil sampling hand probes and augers.




FIGURE 1. Soil sampling hand probe and auger.


You should schedule soil sampling to allow adequate time for soil analysis (~one to two weeks) and fertilizer application, if needed, prior to seeding or planting time. Also, soil tests are representative of current nutrient levels and do not necessarily reflect future conditions. Therefore, soils are ideally sampled yearly in the spring to best estimate growing season nutrient availability; however, it may be more practical to test soil in the fall when soil is dry and there are fewer time constraints. Unfortunately, fall samples do not always represent the true amount of N that will be available at spring planting, because some N is released from organic matter (O.M.) during the winter months in a process called ‘mineralization’. Conversely, soil nitrate can be lost to leaching during wet winters, especially in shallow or sandy soils. Fall N levels will be similar to spring N levels if the fall and winter are cold and dry, because both conditions reduce N mineralization and leaching. Contact your local Extension agent for more information on soil sampling or refer to MSU Extension’s Nutrient Management Module 1 (#4449-1).

Soil Testing Laboratories

The time spent selecting a good laboratory can quickly pay for itself in the form of accurate fertilizer recommendations and desired plant responses. Laboratories that are part of the North American Proficiency Testing Program (NAPTP) should provide you with analysis results of NAPTP soil samples that have known nutrient levels. A fairly high degree of variability has been observed among laboratories (Jacobsen et al., 2002); therefore, it is best to send soil samples to the same laboratory each time to ensure consistency. Regional analytical laboratories are listed in the Appendix.

Some laboratories have standard packages that test for common nutrients and other soil parameters. At a minimum, have your soil tested for N, phosphorus (P), potassium (K), O.M., soluble salts and pH.

Tissue Analysis

In Montana, plant tissue sampled periodically during the growing season and tested for nutrient deficiencies has often led to inconsistent results, due to inconsistent tissue sampling, handling, preparation and shipping (Jackson, pers. comm.). Because it takes a couple of weeks between sending tissue samples, receiving test results, and purchasing/applying fertilizer, plant growth may have already been decreased by the time fertilizer is applied. Therefore, it is recommended that you identify potential nutrient deficiencies by soil testing prior to the growing season. If you decide to tissue test, please contact your local Extension agent for specific information on tissue sampling and sample preparation.

Some nutrient deficiencies can be detected by observing plant growth (Table 2 and Nutrient Management Module 9 for an expanded deficiency key). However, plant

TABLE 1. Standard rates of fertilizer for lawns, gardens and trees/shrubs.


Total Amount

Amount per Application



3 lb N per 1000 sq ft per year

1 lb N per 1000 sq ft

Apply Memorial Day, Labor Day and Columbus Day


20 lb 10–10–10 per 1000 sq ft per year

10 lb 10–10–10 per 1000 sq ft

Apply prior to planting and later between rows to avoid plant burning

Apply 3rd application for high N demanding plantsa


1 lb of 10–10–10 per inch diameter at breast height or 1 lb N per 1000 sq ft drip line

1 lb of 10–10–10 per inch diameter at breast height or 1 lb N per 1000 sq ft drip line

No need for additional fertilizer if plant lies within your fertilized lawn

aBeets, corn, onions, potatoes, rhubarb, spinach, strawberries, sunflowers and tomatoes

Printable version of Proper Watering (PDF)

Proper watering is critical to the success of your plants.

Too much water can be as harmful to your plants as not enough. Many people don’t realize that roots of plants require oxygen. In between soil particles are tiny openings or spaces. In an ideal situation, these gaps should be filled with water and then alternately filled with air. If the spaces are filled with water all the time, there is no oxygen getting to the roots. If there is air between the spaces all the time, there is no water getting into the roots. The oxygen is needed to create the energy the plant uses to take up the water. It is easy to think that because a plant wilts, it needs more water. This is not always the case. If a plant is continually wet, the lack of oxygen to the roots will prevent the plant from using the water available. The roots begin to rot and the plant dies.

This is seen most often with houseplants in the winter when days are short and the weather is overcast. A houseplant can easily go 1 -2 weeks between watering during a NW Montana winter. The plant is essentially dormant.

In the spring, newly planted urns, window boxes and buckets of flowers often have a good deal of extra soil. This soil will hold surplus water. This means that your flowers or vegetables may only need watering every few days. By mid-summer, when the roots have filled the container, these same plants may need water twice a day.

There are some tips to helping keep your roots happy and healthy. The best way to see if your plant needs water is to lift the container. Feel the weight of it when it is wet and then when it is dry. Hot weather can also make a plant wilt. Don’t be fooled into thinking it needs more water on the root system. Check it first.

Make sure your plants are always in containers that have a drainage hole in the bottom. When you water, water thoroughly. If it is an outdoor planter, wash the water through with a hose to keep fertilizer salts from building up. Then let the planter dry out. Don’t put just a little bit of water on every day. Don’t have more than two inches of extra soil around the roots of your indoor plants. Too big of a container holds more water than the plant can use. You can get away with extra soil on outdoor planters as long as you are conservative with the water early in the season. During a rainy spring, you may actually want to tent your planters to keep excess water from drowning your plants.

By mid-summer, many planters and container beds need watering at least once a day. Blossom end rot on tomatoes and potato scab are linked to inconsistent watering. If your planters get overly dry while you are away at work during the day in the hot sun, you may want to consider putting a timer on an irrigation system. While I’m talking about watering, don’t water your garden using an overhead sprinkler. Use a drip or soaker hose. Overhead watering spreads disease in the garden, especially mildews and fungus.

Proper watering goes a long way to ensuring a successful relationship with plants. Being overly liberal with water is as detrimental as overly conservative. Eventually, most gardeners will be able to look at their plants and see if they need water by looking at the color of the foliage and/or very slight flagging. Best of luck and keep on growing.

Proper Watering is Critical to the Success of your Plants Part II

There seems to be a good deal of confusion about watering established trees. More times than not, everyone is consciences about watering a newly planted tree. Two to three times a week on average is good the first season. The water needs to get down about 6-9” so the hose must be set to soak the plant for several hours at a slow drip. Once that first season is over, many people feel the tree should be on its own.

Insects and disease will attack stressed trees first. Wood borers, pine beetles, fungus diseases and weevils are common pests of trees that are suffering from a lack of water.

The most common shade trees in the home landscape are not native to our area. Many of the species have been brought here from the east or west coast where humidity is much higher. 90% of the water in a plant is lost through its leaves. With Montana’s low humidity, the rate of transpiration – loss of water through the leaves – is even higher. These non-native trees require supplemental watering in order to stay in peak condition especially birches and spruces. Maples and Ash will ‘flag’ during times of drought. This wilt is a protective process that decreases the leaf’s surface exposure to the sun. It is the tree’s attempt to reduce transpiration. July and August can be extremely dry in the Flathead. I recommend watering full grown trees at least twice a month during the summer. This would translate into each large tree receiving four 6-8 hour soakings minimally.

The feeder roots of trees are not up against the trunk. They are out at the tips of the longest branch. A soaker hose is a great way to saturate the drip zone without wasting water. The soaker should be allowed to drip until it gets into the ground 1-2”. The rate can be measured by using a tuna can. Just see how long it takes to fill the can twice. This will be how long you want to soak your established trees. Two inches of water should soak down to about 9” into the soil. If you are in heavy clay ground, you may only need to water every 2-3 weeks. If you have sandy or gravely soil, you may need to water every week or two. An average is every two weeks.

Be especially concerned with plants that are under landscape fabric or close to sidewalks and asphalt driveways. The rain does not have the same opportunity to penetrate down to the root system. Supplemental watering may be even more important in these situations.

Lawn sprinklers don’t count when considering the requirements of your trees. Your trees should be on a separate irrigation zone. The lawn is set to 1” per week and that amount of water is usually grabbed by the lawn before ever getting deep enough to impact tree roots. Never water trees with overhead sprinklers, use bubblers, drip irrigation or soaker hoses. Water on the foliage spreads disease such as mildews and other fungus.

Be careful of using mulch against your tree to hold moisture. This can create the perfect home for rodents who will girdle the tree. Mulch against the trunk can rot the tree bark and too much mulch can cause a lack of oxygen and suffocate roots. A small layer of much is beneficial but more is not better in this case. The last comment I will make is that fruit trees require a generous amount of water while fruit is maturing. Water increases the size and firmness of the fruit. Make sure, though, to begin withholding water after September 1st. Reducing water will help the tree to begin hardening off and get ready for winter. Too much water late in the season can decrease winter survival. The exception is evergreens. Evergreens lose moisture from their needles all through the winter. Winter desiccation can be decreased by making sure the ground is damp before the first hard freeze.

The spring of 2016 is quite the opposite of 2015. Water may not be an issue this year but you never know what July will bring. The trees are putting on twice as many leaves and if it turns dry all of a sudden, they will be in real trouble.

If you have any questions, feel free to call the office.

Printable version of Spray Schedule for Apple Trees-WSU (PDF)


222 N Havana Spokane WA 99202 (509) 477-2181 http://spokane-county.wsu.edu/spokane/eastside/ mastergardener@spokanecounty.org


Do not apply pesticides until a specific insect or disease has been positively identified. Using wrong or unnecessary sprays is a waste of time and money and can pose a hazard to people and the environment. Apply pesticide sprays only at the proper time of tree, bud, or pest development. Sprays applied at the wrong time are also ineffective. And always read and follow label directions of the product you use!

For help in identifying home orchard problems or for more complete information on specific fruit pests or diseases, contact your county’s WSU Extension office. TIME



Delayed dormant stage: when just a little green color is showing in buds.

San Jose scale, aphid eggs, mites, Lecanium scale, leafroller eggs.

Horticultural mineral oil spray

Pre-pink stage: before blossom buds show pink color

Powdery mildew disease

Fungicide labeled for powdery mildew control on fruit trees.


Insecticidal soap as needed.

Pink stage: blossoms show pink color just before they open fully.

Powdery mildew

Fungicide labeled for powdery mildew control on fruit trees.

Apple scab disease

Fungicide labeled for apple scab control on fruit trees.

Petal Fall: when 3/4 of petals have fallen off

Powdery mildew

Fungicide labeled for powdery mildew control on fruit trees.

Apple Scab

Fungicide labeled for apple scab control on fruit trees.

Cover Sprays: covers leaves and fruit

Codling moth: start sprays when codling moths begin to appear in traps or 17-21 days after full bloom

Malathion every 10-14 days.

Spinosad every 10 days.

Kaolin (Surround WP)-Keep foliage and fruit coated. May have to reapply

Every 10 days.


Insecticidal soap as needed


Insecticidal soap as needed

Powdery mildew

Fungicide labeled for fruit trees.


Printable version of Spray Schedule for Cherry Trees-WSU (PDF)


222 N Havana

Spokane WA 99202

(509) 477-2181




Do not apply pesticides until a specific insect or disease has been positively identified. Using wrong or unnecessary sprays is a waste of time and money and can pose a hazard to people and the environment. Apply pesticide sprays only at the proper time of tree, bud, or pest development. Sprays applied at the wrong time are also ineffective. And always read and follow label directions of the product you use! For help in identifying home orchard problems or for more complete information on specific fruit pests or diseases, contact your county’s WSU Extension office. TIME



Dormant stage: late winter when daytime temperatures are above 40 degrees.

Coryneum blight


Copper or lime sulfur sprays

Bacterial canker

Copper fungicide sprays

Delayed dormant stage: when just a little green color is showing in buds.

Scale insects, aphid eggs, mite eggs.

Horticultural mineral oil spray

Coryneum blight, Brown rot

Captan, copper or sulfur fungicides

Bloom time

Brown rot

Captan (no copper fungicides)

Shuck Fall: when flower petals have fallen away from young fruit.

Powdery mildew and aphids

Wettable sulfur (not lime sulfur) or insecticidal soap.

Brown rot


Summer sprays: Also called cover sprays because they cover leaves and fruit

Cherry Fruit Fly

Malathion every 10 days beginning when cherry fruits turn yellowish. (Usually late May). Allow 3 days minimum to harvest.

Spinosad when cherry fruits turn yellowish.

Mites, aphids

Insecticidal soaps as needed


Bt as worms begin to feed but before leaves are tightly rolled.

Brown rot


Postharvest: prior to heavy fall rains

Cherry fruit fly

Remove all cherries or continue with malathion or spinosad as long as any cherries remain on the tree. Fruit flies continue to breed in unpicked fruit.

Bacterial canker

Copper fungicide


Printable version of Spray Schedule for Peach and Apricot Trees-WSU (PDF)


222 N Havana

Spokane WA 99202

(509) 477-2181




Do not apply pesticides until a specific insect or disease has been positively identified. Using wrong or unnecessary sprays is a waste of time and money and can pose a hazard to people and the environment. Apply pesticide sprays only at the proper time of tree, bud, or pest development. Sprays applied at the wrong time are also ineffective. And always read and follow label directions of the product you use!

For help in identifying home orchard problems or for more complete information on specific fruit pests or diseases, contact your county’s WSU Extension office. TIME



Dormant stage: late winter when daytime temperatures are above 40 degrees.

Peach leaf curl (on peaches only)

Copper or lime sulfur fungicides

Coryneum blight

Copper or lime sulfur (Do not use lime sulfur on apricots)

Delayed dormant stage: when just a little green color is showing in buds.

Scale insects, aphid eggs, mite eggs.

Horticultural oil spray

Prebloom stage: when just a little flower color shows in the bud but before flowers open.

Coryneum blight, Brown rot

Captan, copper or sulfur fungicides (Do not use sulfur on apricots)

Peach twig borer, aphids


Bloom time

Brown rot


Shuck Fall: when flower petals have fallen away from young fruit.

Coryneum blight, Brown rot


Summer sprays: Also called cover sprays because they cover leaves and fruit

Peach twig borer


Mites, aphids

Insecticidal soaps as needed

Brown rot


Postharvest: prior to heavy fall rains

Coryneum blight

Captan or copper

Peach leaf curl on peaches

Copper or lime sulfur in early February


Printable version of Spray Schedule for Pear Trees-WSU (PDF)


222 N Havana

Spokane WA 99202

(509) 477-2181




Do not apply pesticides until a specific insect or disease has been positively identified. Using wrong or unnecessary sprays is a waste of time and money and can pose a hazard to PEOPLE and the environment. Apply pesticide sprays only at the proper time of tree, bud, or pest development. Sprays applied at the wrong time are also ineffective. And always read and follow label directions of the product you use!

For help in identifying home orchard problems or for more complete information on specific fruit pests or diseases, contact your county’s WSU Extension office. TIME



Dormant stage: late winter as buds begin to swell in February

Pear psylla

Horticultural mineral oil spray

Delayed dormant stage: when just a little green color is showing in buds.

Pear psylla, aphid eggs, blister mites, scale insects, leafroller eggs.

Horticultural mineral oil spray plus lime sulfur (Do not use lime sulfur on d’Anjou pears.)

Petal Fall: when all petals have fallen off

Codling Moth

Malathion every 10-14 days. Begin about 10 days after all petals have fallen.

Kaolin (Surround WP)-Thorough coverage is important.

Summer sprays: Also called cover sprays because they cover leaves and fruit

Codling moth:

Malathion every 10-14 days until 14 days before harvest.

Kaolin (Surround WP)-Keep foliage and fruit coated.

Pear psylla

Insecticidal soap, Kaolin, or Azadirachtin (neem extract) as needed.


Bt as worms begin to feed but before leaves are tightly rolled.

Aphids, mites

Insecticidal soap as needed


Printable version of Spray Schedule for Plum and Prune Trees (PDF)


222 N Havana

Spokane WA 99202

(509) 477-2181




Do not apply pesticides until a specific insect or disease has been positively identified. Using wrong or unnecessary sprays is a waste of time and money and can pose a hazard to people and the environment. Apply pesticide sprays only at the proper time of tree, bud, or pest development. Sprays applied at the wrong time are also ineffective. And always read and follow label directions of the product you use!

For help in identifying home orchard problems or for more complete information on specific fruit pests or diseases, contact your county’s WSU Extension office. TIME



Delayed dormant stage: when just a little green color is showing in buds.

Scale insects, aphid eggs, mite eggs.

Horticultural oil spray

Prebloom stage: when just a little flower color shows in the bud but before flowers open.

Coryneum blight, Brown rot

Captan, copper or sulfur fungicides (Do not use sulfur on apricots)


Insecticidal soaps

Bloom time

Brown rot


Shuck Fall: when flower petals have fallen away from young fruit.

Coryneum blight, Brown rot


Summer sprays: Also called cover sprays because they cover leaves and fruit

Mites, aphids

Insecticidal soaps as needed

Brown rot


Peach twig borer


Postharvest: prior to heavy fall rains

Coryneum blight

Captan or copper