The head is pale brown with a green tinge and mottled with dark brown. Small 6 to 8 inch corn plants are consumed entirely. Larger corn will have the midrib left. Damage starts first at the field edges. The larvae feed at night and hide in the soil during the day.
Armyworms attack all grass-type crops, especially corn and the small grain.
Timothy, millet bluegrass, and some legumes are also attacked. When armyworms are marching, many other plants are devoured. May. Two to three weeks later, adults emerge and lay eggs. There are three generations, and it is usually, but not always, the late generation that does the damage. Fall armyworms larvae have a prominent white, inverted Y-shaped suture on front of head, and hairs arise from black tubercles on the body that are more conspicuous that those on the true armyworm.