This article was originally written by Joel Bagg in 2013. It was edited May 1st, 2023 by Christine O’Reilly to reflect current insecticide options to control alfalfa weevil. Alfalfa weevil can be an issue in Ontario, particularly in south-western parts of the province. While outbreaks tend to be isolated, they can be severe and dramatically reduce forage yield and quality. Typically, alfalfa weevil do not reach significant levels until we are ready to take first-cut. However, sometimes alfalfa weevil larvae development is advanced relative to the alfalfa crop, and can do significant damage before the crop is ready to cut. Control options are to cut early or spray. Insecticides are recommended only when cutting is impractical, such as when the…
