The alfalfa weevil is potentially the most destructive insect pest to alfalfa in southern Ontario.
Crop damage is determined mainly by weevil population and weather conditions.
The warmer climate in southwest Ontario normally advances the development of the weevil several days over that in the eastern counties. Historically, areas close to the Great Lakes experience the worst infestation. The weevil is mainly a pest in first-cut alfalfa, but sometimes regrowth may be damaged if the first crop is cut when the insect is still at early stages of larva. One of the early signs of infestation is this tip feeding. The tip damage resulted mainly from the feeding in the leaf buds.