Where population density is high, they may even lay eggs on other objects. During the 15-21 day worm stage, approximately 85 percent of the foliage consumption of a single caterpillar occurs during the last three to four days. After reaching full size, worms drop to the ground and enter the pupal stage in the soil. The pupal stage varies from 7 to 37 days. In South Texas, the life cycle generally requires 24-30 days.
Fall armyworms vary in color from pale green to almost black.
The adult is an ash-gray moth. Its front wings are mottled and have irregular, white or light gray spots near the extreme tip. Hind wings are white and have a narrow smokey-brown edge. When expanded, the wings are about one and one-half inches across. Preventive treatments normally are not justified because attacks are sporadic.