Fall Armyworm
Egg - Minute, light eggs are laid in clusters of approximately 200 and are covered with grayish, fuzzy scales from the body of the female moth. The eggs become very dark just before hatching.
Larva - The fully grown, green, brown, or black larva is 30 to 40 mm long and has a dark brown to black head capsule usually marked with a pale, but distinct, inverted "Y". Along each side of its body is a longitudinal, black stripe, and along the middle of its back is a wider yellowish-gray stripe. Color plate.
Pupa - The pupa, approximately 13 mm long, is originally reddish brown and darkens to black as it matures.
Host Plants - Corn, sorghum, coastal Bermuda, fescue, and other plants of the grass family are preferred foods. However, the fall armyworm may attack alfalfa, bean, peanut, potato, soybean, sweet potato, turnip, spinach, tomato, cabbage, cucumber, cotton, tobacco, all grain crops, and clover.
Damage - Larvae, often migrating in large armies, are potential pasture pests in late summer and fall. Consuming all above ground plant parts, they are capable of killing or severely retarding the growth of pasture crops. In any case, these caterpillars inevitably lower the forage-producing capacity of a pasture. Even though an important pest of pastures, these larvae are more common on late-planted corn or sorghum (see Corn/Sorghum Fall Armyworm Note).
Life History - Fall armyworms overwinter in several life stages in the tropics, but usually as pupae in the Gulf Coast region of this country. Moths usually migrate into North Carolina during June and early July. New moths may continue to appear until November. Each female lays about 1,000 eggs in masses of 50 to several hundred. Two to 10 days later, the small larvae emerge, feed in clusters on the remains of the egg mass, and then scatter in search of food. Unlike the nocturnal true armyworms, fall armyworms feed any time of the day or night, but are most active early in the morning or late in the evening. When abundant, these caterpillars eat all the food at hand and then crawl in great armies to adjoining fields. After feeding for 2 or 3 weeks, the larvae dig about 20 mm into the ground to pupate. Within 2 weeks, a new swarm of moths emerges, usually flying several miles before laying eggs. Three to four generations occur each year in North Carolina.
The fall armyworm is more difficult to chemically control than the true armyworm but the threshold is the same. The presence of 5 medium to large fall armyworms per 929 cm2 (1 ft2) justifies initiation of control measures. For specific recommendations, consult the current North Carolina Agricultural Chemicals Manual.
