b"War WeedsonCover crops like brown mustard and buckwheat are already being used to control wireworms by some potato producers in Canadabut will they also work to kill problem weeds? Researchers working on an Agriculture and Agri-Food Canada weed control project are trying to find out.BY: MARK HALSALLIN ATLANTIC CANADA, Agriculture and Agri-Food Canada researchers are tackling the thorny prob-lem of herbicide resistance in potatoes by looking into the biofumigant effects of different cover crops on weeds and weed seeds.The research is part of a broader integrated weed management plan for potatoes that's being developed to counter the impact of rising herbicide resistance as well as the potential loss of linuron, a major weed control product and resistance management tool in potatoes under review by Health Canadas Pest Management Regulatory Agency.Andrew McKenzie-Gopsill, an AAFC weed scientist based at the Charlottetown Research and Develop-ment Centre in Prince Edward Island who is leading the initiative, says the cover crop study is focusing on lambs quarters, a triazine-resistant weed thats a common sight in farmers fields across Canada.According to McKenzie-Gopsill, the project is some-what unique in that it utilizes a seed bank-targeted approach to weed management. Lambs quarters is a prolific seed producer, McKenzie-Gopsill says. Were trying to see if we can suppress it with our cover crops as well as to see if theres any effect on that weed seed bank with these cover crops and then various termination methods on top of that.The researchers are analyzing the biofumigant effects of these four different cover crops: brown mustard, buckwheat, timothy, a mix of hairy vetch, crimson clover and annual rye. McKenzie-Gopsill says brown mustard and buck-wheat were chosen for study because theyre already being used in Prince Edward Island as rotation crops for wireworm control. When wireworms eat the roots or the decaying plant matter of brown mustard and buckwheat, it gets converted, from what I understand, into cyanide in their gut and kills them, he says. Andrew McKenzie-Gopsill is an Agriculture and Agri-Food Canada weed scientist.PHOTO: AAFC34 SPUDSMART.COM WINTER 2020"