Several species, which vary greatly in numbers from year to year, may injure corn. See Cutworm fact sheet. European corn borer, Ostrinia nubilalis . The larvae tunnel in the stalk and ears in all directions, weakening the stalks so that they break over. The larva is pale white or gray with black tubercles and is not more than an inch in length when fully grown.
Adults have a wingspread of an inch or so and are buff to brown in color.
There are usually two generations annually. Eggs are laid on the underside of leaves, and the larvae tunnel in the stalks and pupate in the burrows. Second generation larvae and those of the single generation corn borer overwinter in the stalks and pupate in the spring. Control begins with tillage of the corn stubble, either in the fall or early in the spring. This reduces the survival of borers from the previous year.