Alfalfa Weevil Field biology. The adult weevils overwinter in the crowns of alfalfa plants and in debris in and around field edges. Females chew holes in alfalfa stems where they lay 10 to 40 small oval eggs per hole. Egg laying begins in early spring and decreases through June. Larvae are pale green with a white stripe on the back and a shiny black head.
Young larvae feed in the tightly folded leaves of stem buds.
Larger larvae move onto open leaves near the terminals. Peak damaging larval populations often coincide with the first cutting of the crop. Pupation occurs in plant crowns and soil debris. New adults feed for a short time, then become inactive. A second generation of larvae has been observed but is not considered to be important.