Photo and text used courtesy Clemson University
Cooperative Extension Service.

The larvae feed on corn foliage, stalks, and ears, and even funnel in the cob.

This insect is unable to overwinter in South Carolina, but must fly here from much farther south. The moths choose fields thickly covered with grass. If the worms are still unsatisfied when they have eaten all the grass, they start in on the corn. When mature, they enter the soil to pupate. The moths emerge about 2 weeks later.

The first sign of injury appears as broken tassels caused by the borers feeding in the tassel stems. Late in the season its presence is indicated by small round holes at any location on the stalk.

The funneling within the stalks weakens them so that plants break and fall over. As a result, many ears are lost due to spoilage or to being missed by the picker. Feeding on the shank of the ear causes it to fall to the ground.

There are probably three generations a year in South Carolina. Full-grown larvae spend the winter in the stems where they have been feeding, especially down close to the ground.