Corn earworm (extended information)

Helicoverpa zea

Description and life cycle

Upon careful inspection of fresh maize silks or young husks, one may find the small spherical white eggs, which have a shiny appearance and are laid by robust, brownish moths (H. zea). Developing and mature larvae vary widely in color, from brown to green. Because the larvae are cannibalistic, seldom does more than one remain in the ear. Full-grown larvae (4cm to 5cm long) drop to the ground and pupate in earthen cells a few centimeters below the soil surface.

Mechanism of damage

Although they may occasionally feed in the leaf whorl or on the tender tassels, the larvae principally damage the maize ear. They begin feeding soon after emergence, concentrating on the silk channel. In addition to causing direct injury to kernels, they provide a portal for infection by ear rot fungi.