Loopers eat large holes in the leaves and, under high populations, can strip an entire field. Economic infestations of this pest seldom occur before late August or early September. This pest usually occurs in fields that have been previously sprayed. Greenish, brown, or almost black caterpillars with a broad lighter band down each side. Head is prominent and usually yellow or orange.
Caterpillars have five pairs of prolegs with the last pair having the appearance of a forked tail.
When disturbed, they wiggle violently. This caterpillar eats the entire leaf and will strip whole fields when high numbers are present. Pods sometimes will be attacked when defoliation is severe. Olive-green to near black, velvety smooth caterpillar with a stripe down each side. Two black spots are present on the second segment, and there are five pairs of prolegs.