The Cotton Bollworm, or Corn Earworm, Heliocoverpa zea, is a major pest of cotton and corn, but also affects a number of other field crops including soybeans, grain sorghum, sunflowers, and peanuts. It damages cotton plants by cutting off terminals which causes multiple branching and delayed maturity. They also damage the cotton plant by eating into the squares, blooms, and bolls. In corn the larvae feed on the leaves, tassels, ears, and the whorl. In soybeans the larvae feed on leaves, stems, flowers, pods, and seeds within pods that may result in foliage, flower, and fruit loss.
Eggs are a cream color, flattened base, and prominent ribs. They are usually found on the cotton leaves, but may be found on the stems and fruiting forms as well. The mature larvae are about 1.5 inch long and darken before they hatch. The larva can be pink or light green to light brown or almost black on the upper body. While the underside is lighter with horizontal stripes running along the back. The body is sparsely covered with dark colored hairs. The moth stage has a wing span of approximately 1.5 inches. The fore wings have dark irregular bands near the edge with an indistinct dark spot near the middle of the front margin and the hind wings are light gray with dark bands on the trailing margins.
They overwinter as pupae in the soil and moths emerge in the spring to lay eggs singly on host plants. A female moth may lay 1000 or more eggs in an 8-10 day period. Larvae hatch from the eggs in 3-5 days and undergo 6-7 molts in about 16 days finally reaching a length of about 1.5 inches. Upon reaching maturity the larvae drop to the soil and pupate burrowing into the soil to a maximum depth of about 4 inches. In about 10-12 days the moths begin to emerge from the pupal stage. This cycle from egg to adult is about 30 days and there are multiple generations of them each year.