Resistance to glyphosate has not officially been confirmed in Canada fleabane populations in Western Canada, but the weed, sometimes called horseweed or marestail, should be on the radar when it comes to herbicide resistance on the Prairies, according to Manitoba Agriculture’s weed specialist.
Canada fleabane that’s resistant to glyphosate and other chemistries is already established across the border in North Dakota and South Dakota. It was first found in Ontario in 2010.
“I say this is our next bad news story,” says Kim Brown-Livingston, joining us for this Wheat School episode filmed at Manitoba Crop Diagnostic School in Carman.
“A lot of farmers are not familiar with this weed at all, so even just to get familiar with it is important. It’s not bad news yet, but I have a feeling that it’s coming. And I think it could be coming in the next few years,” she says.
With tiny seed that can float for miles on the wind and germinate on the soil surface, Canada fleabane tends to be a problem in cereal crops and forage seed fields, proliferating in zero-till situations, she notes.
Traditionally, it’s been seen as a weed that grows in the ditch or on field edges, but Brown-Livingston says she’s seeing an increasing number of cases where fleabane is growing and blanketing the ground in seeded areas.
As for testing for resistance, she says work is underway to determine if quick diagnostic DNA tests used in other areas will work in Manitoba. If herbicide resistance is suspected, she suggests sending seed to a lab to be grown out, and then adjusting fall weed control programs accordingly.