Glyphosate-resistant kochia is spreading quickly across the Prairies, but right now farmers are only seeing the “tip of the iceberg”, according to the weed specialist with Manitoba Agriculture.

Kochia populations showing some level of glyphosate resistance in Manitoba rose from one per cent in 2013 to 59 per cent in 2018, according to the latest weed survey results from Agriculture and Agri-Food Canada. Alberta saw a similar increase, rising from five per cent in 2012 to 50 per cent of kochia populations in 2017 (Saskatchewan’s 2019 survey results have not yet been published.)

“When we looked at the testing results, a lot of those fields came back with a low level of resistance — that’s the number of plants within the population that are resistant, not how much herbicide it takes to kill it,” explains Tammy Jones in the interview below, recorded at the CropConnect Conference at Winnipeg.

“So I don’t think we’re aware they’re there because we’re used to there being a few weeds left in the field at the end of the day…,” she notes.

“If it’s only two out of eight plants that don’t die, we’ll probably make some other excuse for it. We’re not going to think herbicide resistance. So I think it’s a tip of the iceberg thing.”

And in the next five to 10 years, Jones thinks we will only see more problems, highlighting a need to use many approaches to weed management.

“There are lots of tools…there are many tiny hammers, but it’s how do we use all those tiny hammers together to the best effect,” says Jones. “So we talk cover crops, we talk intercropping, we talk changing your seeding date, your crop rotation, even narrowing your rows…the problem is there isn’t a one-size-fits-all…”

Jones says it’s a complicated problem, and with no simple recipe, and not a lot of new modes of action being discovered, it’s going to take a lot of work.

Listen to Tammy Jones discuss the prevalence of glyphosate-resistant kochia and tools for preventing its spread with Kelvin Heppner at CropConnect:

Related: Prairie farmers facing increasing herbicide resistance pressure

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