Group 2 herbicides off limits | Researchers will survey fields in the Warner area this summer to determine its spread
Weed scientist Bob Blackshaw asked more than 350 farmers not to shoot the messenger Jan. 31 when he told them glyphosate resistant kochia was living among them.
News that the resistant weed had been discovered in southern Alberta was initially released in mid-January, but the Agriculture Canada researcher provided an update for farmers living in the heart of the problem area.
“This is the first case of a glyphosate resistant weed in Western Canada. Not a total surprise to us, but I guess we hoped we were wrong. But we weren’t wrong,” Blackshaw told the biannual Irrigated Crop Production Update in Lethbridge.
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He said he received a call last August from a farmer near Warner, Alta., who told of kochia survival in a chem-fallow field that had been sprayed twice with glyphosate at a fairly high rate.
Such calls aren’t unusual, said Blackshaw, and are usually a matter of chemical misapplication. However, the more he heard about it, the more concerned he became.
“My spidey sense sort of went off on this one, and I thought, ‘OK, I think there’s a good chance it’s real.’ ”
He called fellow scientist Hugh Beckie in Saskatoon, who joined Blackshaw to investigate the weeds. They had both previously seen photos of glyphosate resistant kochia in Kansas, first discovered in 2007, and the pattern in the Warner area fields matched those in Kansas.
The resistant plants tend to appear in linear patterns because when they become tumbleweeds, they scatter seeds as they roll.
The two scientists collected plants from three fields in three locations owned by three farmers in the region. They tested them, and all samples have proven to be resistant.
Blackshaw said research is underway on potential management practices to control kochia, but the herbicide arsenal is smaller than it used to be.
“I do just want to remind everybody here that Group 2 herbicides are not going to work on kochia in southern Alberta,” Blackshaw said.
That means Refine, Express, Pursuit, Odyssey and Solo will not work on kochia. He said Group 14 herbicides, which have a new mode of action, might have promise, but studies will reveal more.
Though the weeds appeared in fields near Warner, Blackshaw said they aren’t necessarily the initial source.
The extent of spread is also unknown so a larger survey will take place this summer.
Meetings are planned in Milk River and Foremost March 8 to discuss the problem with farmers.
Blackshaw recommended farmers visit www.weedtool.com, where a questionnaire can help them assess their risk of weed resistance.
