Baseline survey of herbicide resistance in Russian thistle (Salsola tragus L.) finds no resistance in Manitoba

Russian thistle is a tumbleweed that is problematic in the semi-arid regions of the Northern Great Plains. Russian thistle with resistance to group 2 herbicides has been found in Saskatchewan and Alberta, while glyphosate (group 9)-resistant biotypes have been found in western United States bordering Canada. Herbicide-resistant Russian thistle can evade herbicide control and result in significant crop yield losses. A Manitoba survey of Russian thistle populations collected in 2018 found that the Russian thistle collected from Manitoba did not exhibit resistance to herbicide groups 2, 4 or 9. This research suggests that kochia populations in Manitoba remain herbicide-susceptible. This is good news for Manitoba farmers because the herbicides used to manage Russian thistle remain effective in this province.