When warm spring temperatures return, armyworm feeding resumes. Armyworms may move onto corn during this period. When feeding is completed, larvae pupate just below the surface of the soil. Adults of the first generation emerge in April and May and feed on nectar for 7 to 10 days before beginning to lay eggs. There are three to four generations per year in Kentucky.
Armyworms usually feed at night and damage corn by chewing leaves.
They prefer to feed on the succulent leaves in the whorl first. Feeding is usually confined to leaf margins, but occasionally they may strip the entire plant leaving only the midrib of the leaves. During the day, armyworms are found in the soil or underneath ground cover. Ragged leaf feeding in the spring and early summer is evidence of armyworm feeding. Corn can usually recover from light to moderate feeding by armyworm without significant yield loss.