Working together to strengthen and support noxious weed management efforts in Montana.

Integrated Weed Management Articles

MSU: Report for the Montana Noxious Weed Trust Fund Advisory Council

Friday, June 17th, 2016


MSU AnnualReport MNWTF June 2016 cover imageMontana State University: Montana Agricultural Experiment Station and Extension Service

This report for the Montana Noxious Weed Management Advisory Council was assembled in compliance with the Montana Noxious Weed Trust Fund Act and Administrative Rules which require an annual report from the Montana Agricultural Experiment Station and Montana State University Extension Service on current projects and future plans. This report is a compilation of major weed science research and education activities conducted by MSU over the past three years and includes comprehensive reporting of all weed science research products and education funding and activities.


Tracy Sterling and Steve Siegelin

Tracy M. Sterling
Professor & Department Head
Department of Land Resources & Environmental Sciences
334 Leon Johnson Hall
Montana State University
P.O. Box 173120
Bozeman, MT 59717

Phone: (406)994-4605
FAX:   (406)994-3933

Phragmites ID

Saturday, October 31st, 2015


Find out all about these invasive species by clicking HERE.

Mode of Action – Powerpoint Presentation Ready for Use

Friday, May 17th, 2013


This came from the October 2013 MSU presentation.   By request they have made this available to you for your use.

Download the MSU mode of action presentation

Weeds and Wildfire – October 2012 MSU Weed Post

Monday, October 1st, 2012


The October Weed Post, featuring weed management after fire is available from MSU.  The hot, dry, and fiery summer experienced in much of Montana and many other states in the Rocky Mountain region has prompted a great deal of interest in weed management following wildfire. Weed response to fire is dependent on many factors including propagule pressure (reproductive structures like seeds and root fragments, both above- and belowground), time since invasion, competition with desired vegetation, disturbance history, rainfall patterns, soil characteristics, plus the actual dynamics of the fire itself (e.g. temperature, duration, season), and the type of plant community where the fire burned, for example mountain grasslands versus lodgepole or ponderosa pine forest. Weed response to fire also depends on the regeneration strategy of the weed species of concern. Research suggests that most post-fire plant cover originates from resprouting. So, weeds that resprout from vegetative structures may respond quickly following fire as compared to weeds that have to regenerate from seeds.

Download the October 2012 MSU Weed Post – Weeds and Wildfire

Rangeland Revegetation Revisited: Do short-term results predict long-term outcomes of revegetation? – MSU September Weed Post

Saturday, September 1st, 2012


The September Weed Post  features a recent publication on the long-term outcomes of revegetation on spotted-knapweed infested rangeland in western Montana.  I hope you will find it thought-provoking and useful.    Download and this new publication from Montana State University – September 2012 MSU Monthly Weed Post

MSU: Get Ready For Fall Weed Control

Friday, August 20th, 2010


We unusually think of weed control as a spring chore, but there are options in the fall that will help in the following year.  Montana State University published an article about getting ready for fall weed control. The following is an excerpt from it.

As fall temperatures begin cooling, growers across the region have an opportunity to control winter annual and perennial weeds. Understanding how weeds grow, and learning key control concepts will enhance producers’ ability to reduce the spread and impact of weeds this fall. This article provides tips to manage winter annual weeds in small grain farming systems and reviews several concepts for managing perennial broadleaf weeds.

Click here to read the complete article.

Learn About Calibration for Using Herbicides

Thursday, August 19th, 2010


One of the most important things that can be done when using herbicides is making sure you are spraying the right plant and you are using the right amount of herbicide.  Learning how to use the right amount of herbicide is called calibration.

There are many ways a person can learn about calibration.

  • Contact your local weed coordinator or extension agent.
  • Attend a Private Applicator’s Class in your area.
  • Use a combination of print and video materials available.

The following are some of the print materials available.  We have provided links or you may contact your extension agent.

MWCA helped to underwrite this short video that demonstrates calibration of equipment.  We have broken it down in to 6 steps.

Chapter 1 Importance of Calibration

Chapter 2 Equipment & Pre-Calibration Check

Chapter 3 Understanding Calibration

Chapter 4 Calibrating Backpack Sprayer and Handline

Chapter 5 Calibrating Using the Strip Method

Chapter 6 Adding Pesticide to Your Tank

MSU Extension also has a DVD available for purchase on their website. There is also information on the MSU Webpage on Calibration.

Compatibility of Seed Head Biological Control Agents and Mowing for Management of Spotted Knapweed

Monday, April 5th, 2010


Authors: Jim M. Story, Janelle G. Corn, and Linda J. White

Summary: Seed head insects, primarily the seed head fly, Urophora affinis, and the seed head weevils, Larinus spp., are reducing spotted knapweed seed production by about 94% in most areas of western Montana. Studies were conducted on the compatibility of seed head biological control agents and mowing for management of spotted knapweed.  Our study demonstrated that mowing of spotted knapweed in the spring and early summer can result in the growth of secondary flower buds which escape attack by seed head biocontrol agents, thereby allowing the knapweed to produce a nearly-normal complement of seed.  Therefore, we conclude that the historical practice of mowing spotted knapweed during the spring and early summer with no follow-up mowings should be avoided if large populations of seed head biocontrol agents are present.

Download a copy of the research article.

Influence of Seed Head-Attacking Biological Control Agents on Spotted Knapweed

Wednesday, March 24th, 2010


Complete Title: Influence of Seed Head-attacking Biological Control Agents on Spotted Knapweed Reproductive Potential in Western Montana over a 30-year Period

Authors: Jim M. Story, Lincoln Smith, Janelle G. Corn & Linda J. White

Summary:  Studies were conducted on the impact of seed head insects on spotted knapweed reproductive potential in western Montana over a 30-year period.  Results indicated that seed head insects are reducing seed production by about 94% in many areas of western Montana.  The reduction of knapweed seed production has resulted in a 98% reduction in the knapweed seed bank which, in turn, has contributed to the decline of knapweed in these areas.  Of the seed head insects, the fly, Urophora affinis, and the weevils, Larinus obtusus and L. minutus, are having the greatest impact on knapweed seed production.  The current decline of spotted knapweed in many areas is likely due to the impact of the seed head insects on the knapweed seed bank and the effects of the root weevil, Cyphocleonus achates, on mature plants.

Download a copy of the research article.

Decline of Spotted Knapweed Density in Montana with Large Populations of the Root Weevil

Monday, March 15th, 2010


Full Article Name: Decline of spotted knapweed density at two sites in western Montana with large populations of the introduced root weevil, Cyphocleonus achates (Fahraeus)

Authors: J.M. Story, N.W. Callan, J.G. Corn, L.J. White

Summary:  Spotted knapweed plant density was monitored over a 11-year period (1993-2004) at two sites in western Montana where the root weevil, Cyphocleonus achates was released.  Spotted knapweed density declined significantly over time at both sites (99% and 77%, respectively), after C. achates numbers increased dramatically at both sites.  The current decline of spotted knapweed in many areas is likely due to the effects of C. achates on mature knapweed plants and the impact of the seed head insects on the knapweed seed bank.

Click here to download and read the complete article.