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Herbicide Resistance Resources

Herbicide-resistant weeds are becoming increasingly common in the Pacific Northwest, threatening the economics and sustainability of farming systems. Herbicide-resistant weed biotypes are selected for and will increase in the population through repeated use of the same or similar herbicides. Italian ryegrass, downy brome, wild oats, Russian thistle, mayweed chamomile, and prickly lettuce are just a few of the many weed species with biotypes resistant to commonly used herbicides. The resources on this page will help you understand how herbicide resistance occurs, how to manage weeds to slow the rate of herbicide resistance development, and what to do if you suspect you have a resistant biotype on your farm.

WSU Wheat Beat Podcast Episodes


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Herbicide resistance is a problem that has quickly spread throughout the wheat growing regions of the inland Pacific Northwest. Overreliance on herbicides for the management of weeds is a major cause of herbicide resistance. Integrated weed management relies on a wide range of practices to manage weeds and slow the development and spread of herbicide resistance. This publication presents growers and farm managers with best management practices (BMPs) that can be incorporated into farming systems to manage herbicide resistance. A table toward the back of the publication (Table 3) allows readers to identify practices that are already being used and additional practices that should be implemented.


Tools

Herbicide Resistance Weeds Map

Functionality: The Herbicide Resistance Weeds Map allows you to see what herbicide-resistant biotypes have been identified in counties in eastern Washington and adjoining counties in Idaho and Oregon. New

Herbicide Resistance Weeds Map

Herbicide Mechanisms of Action: Wheat

Functionality: Allows growers to query a database of herbicide trade names, active ingredients, mechanisms of action, and Washington weed species with confirmed resistance to one or more herbicides. Growers can search by trade name to find out what active ingredient(s) are in a herbicide product, what mechanism(s) of action the active ingredient(s) represent, what chemical family each active ingredient is in, and whether there are any weed biotypes in Washington with confirmed resistance to that mechanism of action.

Herbicide Mechanisms of Action: Wheat

Herbicide Mechanisms of Action: Pulse Crops

Functionality: Like the tool for wheat, the pulse crops tool allows growers to query a database of herbicide trade names, active ingredients, mechanisms of action, and Washington weed species with confirmed resistance to one or more herbicides. Growers can search by trade name to find out what active ingredient(s) are in an herbicide product, what mechanism(s) of action the active ingredient(s) represent, what chemical family each active ingredient is in, and whether there are any weed biotypes in Washington with confirmed resistance to that mechanism of action. The tool also allows growers to search the database by active ingredient, mechanism of action group, or resistant weed.

Herbicide Mechanisms of Action: Pulse Crops

Winter Wheat Herbicide Efficacy Tables

Funcationality: Use the dynamic Winter Wheat Herbicide Efficacy Tables to find the most effective herbicide options for the control the weed species you are most concerned with in your winter wheat crop. The tables will sort the herbicide options to show you the best treatments for the selected weed species.

Winter Wheat Herbicide Efficacy Table

Additional Resources

YouTube Video

Integrated weed management (IWM) strategies are critical for effective long-term management of weeds in the agroecosystem. This video summarizes the biological framework for integrated weed management and summarizes an approach to developing a weed management plan.

Wheat Academy Presentations

Wheat Academy logo with WSU cougar.

Ian Burke’s presentations:

Washington State University