Caterpillars hatch from eggs in about 10 days and begin feeding together, first on the remains of the egg mass and then on the host plant. The pupa is about inch long, reddish brown to black, smooth and hardened. Adults emerge in about 2 weeks. Several generations can occur annually. It is most common in late summer or fall.
Caterpillars have chewing mouthparts.
Adults have siphoning mouths. Fall armyworms feed on a wide range of plants, including Bermudagrass, corn, fescue, Johnsongrass, rice, ryegrass, small grain crops, sorghum, Sudangrass and timothy. In corn, caterpillars can injure foliage as well as the ears. Caterpillars often occur locally in large numbers and migrate together like an army as they devour host plants, eating all above ground plant parts. They feed at all times of the day or night.