The Latest on Herbicide Resistance & Weed Management in Montana

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GROW recently caught up with Montana State University weed scientists, Dr. Tim Seipel and Dr. Lovreet Shergill, for a deep dive into the most problematic herbicide-resistant weeds in Big Sky Country and farmers’ integrated weed management (IWM) options for managing them. 

Dr. Lovreet Shergill (left) and Dr. Bill Curran stand near a kochia infestation in a Montana wheat field. (Photo credit: Claudio Rubione)
Dr. Tim Seipel, in a Montana wheat field. (Photo credit: Claudio Rubione)

Dr. Seipel gave an overview of weed problems for southwest and western Montana. Over many decades, many producers there have transitioned from cattle ranching and wheat farming  to more diverse operations that include wheat, barley, hay and pulse crops, all grown in the shadow of the Rocky Mountains. Dr. Shergill covered southeastern Montana, a region within the northern Great Plains, where corn, sugar beets, wheat, barley, cattle and hay round out the agricultural landscape.

Kochia, king of the western weeds, tops both scientists’ lists of problem weeds, as it continues to evolve resistance to a growing list of herbicide groups. Other weedy contenders are also putting up a fight against chemical control, including wild oats, green and yellow foxtail, Russian thistle, downy brome (cheatgrass), lambsquarters, and redroot pigweed. 

See the full details on the status of these weeds and their herbicide resistance here: 

With herbicides struggling against these weed populations, farmers need to look to other weed management strategies, Dr. Seipel and Dr. Shergill explained. In this video below, they discuss the benefits of a range of IWM strategies, including: 

  • Crop rotation and continuous cropping 
  • Field mapping and precision spray or tillage technology 
  • Harvest weed seed control (seed impact mills and chaff Lining) 
  • Cover crops 
  • Residual herbicide use & robust tank mixes 
  • Planting date & seeding rate adjustments

Watch the full video here:

See more information from GROW on the integrated weed management strategies of cover crops, harvest weed seed control, mechanical weed control and cultural crop management strategies such as crop rotation, row spacing and scouting. 

Videos by Claudio Rubione, GROW; editing and sourcing by Bill Curran; text by Emily Unglesbee, GROW