The first symptom is wilting of the top leaf. Infested corn plants may be recognized by the leaves turning dull green first, then brown from the tip downward, followed by a general withering and collapse of the plant by the time seedlings are 4 to 10 inches in height. The hollowed-out stalk at ground level allows the upper portion of the plant to break off or to be pulled off with ease. The pink-purple larva is usually found in the stalk or in soil near the base of the plant. Damage may vary from negligible to near total seedling loss.
Damage varies from season to season, especially as weed control fluctuates.
The adult is a brown, medium-sized moth that emerges in August from its pupa near the soil surface. During September, the female lays 50 to 75 eggs in parallel rows on the leaf sheath of weed grasses in grassy fence rows and borders, or in surrounding weed cultivated fields. Quack grass is a common host. The overwintering eggs hatch in May, and the small larvae bore into the stems. By early summer, they have outgrown the stems of their primary hosts and migrate to larger, stalked weeds and cultivated crops.