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.
Timely Topics
Resistance Testing Program
Submitting a sample to the WSU Resistance Testing Program is easy. View the Resistance Testing Program webpage for detail about how to submit samples.
GROW is a scientist-led network coordinating research to help farmers across the U.S. fight herbicide-resistance with a greater diversity of weed control strategies. The GROW website and social media platforms provide information, videos, tools, news stories and other resources on integrated weed management options such as cover crops, increased crop competition, harvest weed seed control, weed seedbank prevention and more.
PNWHRI Problem Weeds Survey QR Code
Hold your phones camera up to the code and select the pop-up link to access the survey.
WSU Wheat Beat Podcast Episodes
Featured Article
- From CAHNRS News: Australian professor shares herbicide resistance knowledge during WSU visit New
Featured Publication
Related Publications
Weed Control Reports Excerpts
2019 Weed Control Reports
- Management of ALS-resistant Italian ryegrass with pyroxasulfone and sulfosulfuron in winter wheat (pdf)
- Italian ryegrass management with pyroxasulfone and sulfosulfuron in spring wheat (pdf)
- Evaluation of Axial Bold for wild oat control in spring wheat (pdf)
- Evaluation of preemergence herbicides for the control of Russian-thistle in chemical fallow (pdf)
- Postemergence weed management in fallow using weed sensing spray systems (pdf)
2018 Weed Control Reports
- Crop Tolerance of Talinor™ with Slow Release Fertilizers in Winter Wheat and Mayweed Chamomile Control (pdf)
- Postemergence mayweed chamomile management in winter wheat without clopyralid (pdf)
2017 Weed Control Reports
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 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: 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.
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.
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
Ian Burke’s presentations:
- 2018 Wheat Academy – Integrated Weed Management (pdf)
- 2016 Wheat Academy – Herbicide Resistance (pdf)
Publications
- Advances in Dryland Farming in the Inland Pacific Northwest – Chapter 9 (pdf)
- Herbicide Resistant Weeds and Their Management (pdf)
- Management Strategies for Preventing Herbicide-Resistant Grass Weeds in Clearfield Wheat Systems (PNW 572)
- Strategies to Minimize the Risk of Herbicide-Resistant Jointed Goatgrass
If you require an alternative format for any of the content provided on this website, please contact us at small.grains@wsu.edu.