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Yikes! Herbicide-Resistant Weeds Discovered

Ontario Farmers Faced with Long List of Resistant Weeds

By , Farms.com

Farmers in Southwestern Ontario are facing a growing list of herbicide-resistant weeds. The herbicide resistance is weighing down fruit and vegetable farmers in the region.  The Ontario Ministry of Agriculture Food and Rural Affairs weed specialist representative Kristen Callow spoke at the Vegetable Crop Open House at the University of Guelph’s Ridgetown Campus where she highlighted some of the growing concerns among fruit and vegetable growers. She says that the newest threats are large crabgrass in onion and carrot fields.

The threats are serious because the resistance is now found in all ‘Group One’ grass and farmers don’t have any alternatives to control the pests for the growing season. Other weeds that farmers need to be weary of are glyphosate-resistant fleabane and ragweed that can be toxic and are spreading across the province. Both weeds spread rapidly because the seeds travel on the wind. Many fruit orchards in the province are battling the weeds that are being spread through seed carry over from the wind.


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This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under agreement number 2023-38640-39573 through the North Central Region SARE program under project number ENC23-226. USDA is an equal opportunity employer and service provider. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S. Government determination or policy.