Montana farmers already struggling with severe drought conditions could be facing another threat to their crops.
Scientists with Montana State University’s agriculture research center are investigating the infestation of possible glyphosate-resistant kochia in north central fields near Gildford and Hingham, and in newer areas west near Rudyard, Inverness and Joplin.
Kochia is a fast-spreading tumbleweed that can grow seven feet tall and damage wheat-fallow cropping systems. Glyphosate is an active ingredient in herbicides like Roundup. Kochia that resists glyphosate has proliferated in recent years throughout Kansas, Nebraska and Colorado and most recently into Alberta, Canada.
“There is a chance of that rapid expansion of the population, which would be a serious concern,” said Prashant Jha, an associate professor at MSU and scientist at the Montana Agricultural Experiment Station’s Southern Agricultural Research Center based in Huntley.
This is the first report of glyphosate-resistant kochia in the state, though Jha and his team of scientists are in the process of officially confirming the kochia’s resistance. Seeds will be collected this fall and screened through lab work, Jha said. The research will identify whether adaptation has taken place and, if so, what possible strategies exist for combating the resistance. The findings could be released by next spring, Jha said.
“Surely we need to manage this, otherwise it will be a great concern,” Jha said.
Kochia infestation has historically been less of a concern in Northwest Montana, where a more diverse cropping system exists year-round compared to areas east of the Continental Divide.
“Kochia doesn’t grow very well in this area,” said Bob Stougaard, an MSU professor and weed scientist with the Northwest Ag Research Center in Kalispell. “We have some kochia in this part of the state but not very much. It isn’t very prevalent.”
Growers in this part of Montana work without a fallow period, meaning they can cycle through crop rotations annually, which has proven to be a successful defense against all weeds, including kochia. Stougaard also said a large number of local growers still use tillage, like plowing, as opposed to heavy amounts of herbicides. Tillage helps control weeds and reduces growers’ reliance on herbicides, shrinking the likelihood of a resistant population developing.
“Because we aren’t using herbicides as intensely we are not seeing the development of resistant weeds as rapidly as (other areas of Montana),” he said, adding it is still possible, like the FarGo-resistant wild oats discovered in the 1990s.
Roundup-resistant weeds like kochia have invaded roughly 14 million acres of cotton, soybean and corn nationwide, according to Syngenta AG, a global provider of seeds and pesticides. That number is likely to double by 2015, the company announced last year.
“It is critical for farmers to know we could have this resistant strain of kochia,” Jha said.
To defend against resistance development, growers should always use the recommended rate of herbicide, Jha said, instead of a lower amount. Rotating different types of herbicides and diversifying crop rotations if possible can be other effective combative efforts, he said.
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