After 10 days, adults emerge. Adults then enter a period of reduced activity for the duration of the summer, and resume feeding and oviposition in the fall. Oviposition may occur anytime between mid-August through winter freeze. Only one generation occurs per year. Damage Both adults and larvae cause feeding damage to alfalfa, though the larvae cause more damage than the adults do.
Heaviest damage is inflicted early in plant development.
Intense early season feeding compromises the quality and yield of the first cutting of alfalfa. Warm areas of the field show signs of damage first. Larvae skeletonize leaves and destroy leaf buds, mainly on the terminal portions of the plant. Older larvae feed on mature leaves, giving them a skeletonized appearance. Adult beetles notch stems and shoots, sometimes completely severing shoots and leaf stems from the plants.