Ian Burke

Ian Burke, a weed science professor at Washington State University, is part of a team of researchers working on solutions to the spread of weed-resistant weeds in the Northwest.

Researchers want to hear from Northwest farmers about weeds that have become resistant to herbicides.

According to the Weed Science Society of America, once a weed population is exposed to a herbicide to which one or more plants are naturally resistant, the herbicide kills susceptible individuals, but the resistant ones survive and reproduce.

With repeated herbicide use, resistant weeds that initially appeared as isolated plants can spread to dominate the field.

“On a weed-for-weed basis, it could be grim to potentially OK,” said Ian Burke, weed science professor at Washington State University.

Some areas have glyphosate-resistant downy brome, which means growers must fundamentally change how they farm if they’re in a wheat-fallow system. In those areas, no post-emergence herbicides, or Group 2, are available to manage the weed in wheat, Burke said.

Herbicide-resistant Russian thistle and Italian ryegrass are increasingly problems in some areas.

“Once they’re in the crop, they’re in the crop,” Burke said. “We’re not able to control them unless it’s by mechanical implement.”

Because of the lack of post-emergence herbicides, some farmers have started planting CoAXium wheat, with a patented herbicide-tolerant trait and accompanying post-emergence Agressor herbicide.

The owners of the system want to adapt wheat varieties for the region, Burke said.

“But the growers are too impatient, they have too much of a downy brome problem so they’re going ahead and planting non-adapted varieties in an attempt to kill the downy brome they have with this Aggressor herbicide,” Burke said. “Once they’ve used up all the Group 2 herbicides and then they go to this Aggressor herbicide, it’s only a matter of time before that fails too. And then that’s it.”

Burke, fellow WSU weed researcher Drew Lyon, and University of Idaho post doctoral research associate Katie Dentzman will host a panel about the situation at 7 a.m. Nov. 15 during the Tri-State Grain Convention.

Other speakers during the discussion are UI area extension educator Douglas Finkelnburg and Idaho farmer Steve Riggers.

Dentzman holds a second listening session at 10:30 a.m., the same day at the convention.

The researchers ask that farmers RSVP to ensure space.

Anyone is encouraged to participate, Burke said.

“We know we need more focused effort on this issue,” Burke said. “There’s just not that many weed scientists left in the tri-state area.”

Australian farmers and researchers have implemented a herbicide resistant initiative to help growers fight resistant weeds. Burke hopes to develop a similar program for the region, finding a larger group with more funding available to tackle the problem.

The researchers want to understand where farmers are in their decision-making process. It could ultimately allow them to find new ways to talk to farmers and make sure solutions fit into their existing farming methods, Burke said.

For example, Burke doesn’t want to go into a room full of no-till farmers — growers who cut crops and leave remaining organic matter behind without disturbing the soil — and tell them the solution involves tillage.

Dentzman cites “techno optimism,” for growers’ belief that a new herbicide will come to the rescue

It means weed researchers have failed to communicate how “dire” the problem really is, Burke said.

Farmers would be better able to control the weed in a farming system that includes canola or winter peas, since herbicides can be still be used on those crops, rather than continuing to grow winter wheat in the face of increased resistance.

But some growers might not be prepared to switch to the new crops, Burke said.

“The end of the line is in sight,” he said. “These (herbicides) are very susceptible to resistance development. We’ve already detected it in downy brome, so we know it can happen quickly. That’s the difficult choice they face.”

Burke hopes the sessions raise grower awareness and allow them to share information.

“In many cases over my career, I’ve found that an innovative grower has found the solution to a problem I’m trying to solve already.”

Contact Burke at 509-335-2858 or icburke@wsu.edu

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