Researchers find jointed goatgrass resistant to Beyond herbicide

Jointed goatgrass resistant to Beyond herbicide has been found in Eastern Washington, according to researchers.

BASF’s Clearfield technology allows farmers to use imidazolinone herbicides, marketed under the Beyond trade name, to combat weeds such as jointed goatgrass.

The jointed goatgrass found is resistant to imazamox, the active ingredient in Beyond.

The resistant biotype — a group of genetically identical plants within a species — is 144 times more resistant than other goatgrass plants, according to Washington State University researchers. To see even a little response in the resistant plants, researchers had to use six times the labeled use-rate of Beyond.

“It’s definitely of concern, because there’s only one herbicide that controls jointed goatgrass,” said Ian Burke, an associate professor of weed science at WSU. “It’s a big deal because we grow a lot of seed wheat. It can’t have any jointed goatgrass in there. If this were to become widespread, we would have some real problems.”

The resistant plants were found on one farm, Burke said. He declined to identify the farmer.

Burke believes his research team will be able to kill all the resistant plants, but he said other resistant plants could appear.

“We don’t know if this particular biotype might have spread. We don’t think so,” he said. “We know there’s widespread use of Beyond in the region for jointed goatgrass management.”

It’s just as likely that another biotype could have developed resistance, Burke said.

The resistance developed because of the repeated use of Beyond, he said.

“I don’t want to suggest that the grower disobeyed (BASF stewardship guidelines), but just because of the rotation he was in, it was the ideal conditions to set it up for failure,” he said.

In a statement, BASF said it supports the university’s research to preserve the long-term benefits of the Clearfield wheat production system.

“Wheat producers are asked to help protect and prolong the usefulness of these technologies and requirements highlighted in the Clearfield stewardship guidelines to help prevent the onset of herbicide resistance in weeds,” BASF stated.
Burke recommends farmers use information about managing jointed goatgrass without Beyond herbicide, including cultural and mechanical options.

“Given current financial constraints wheat growers face with low commodity prices, some of those might be more palatable, depending on the size of the infestation,” Burke said. “I always encourage growers to think about all the different solutions they could be using before choosing to use the Beyond system.”

Burke hopes to help growers with herbicide stewardship.

“It’s just another example of how our reliance on herbicides is quite tenuous,” he said. “We really need to be exploring as many options as possible.”