Preventive measures can control the spread of herbicide resistance, but when they stop working, the best tool is rapid detection. Dr. Martin Laforest, a weed scientist at Agriculture and Agri-Food Canada’s Saint-Jean-sur-Richelieu Research and Development Centre and his team have developed molecular tests that can detect the presence of herbicide resistance in less than two weeks using only leaves from the noxious plant.
In Canada, weeds in vegetable crops cause tens of millions of dollars in losses every year. Being able to act swiftly is essential because each resistant plant that releases seeds creates a bank of resistance-carrying seeds in the soil. A zero-tolerance approach is needed: all plants that can resist a given herbicide must be eliminated.
These genetic tests have been used in a research setting to characterize suspected resistance cases since 2015. This year, they moved to the field: the Laboratoire d’expertise et de diagnostic en phytoprotection of the Quebec Department of Agriculture, Fisheries and Food (MAPAQ) now offers an herbicide resistance screening service to Quebec producers free of charge.
Research is ongoing, and discussions are underway between MAPAQ and the Ontario Ministry of Agriculture, Food and Rural Affairs to allow the use of these markers in Ontario.
Once they are widely known and used, these molecular tests may help slow the spread of herbicide resistance, promote the implementation of strategies to manage resistance, and limit the economic impact of herbicide resistance across Canada.