This pest is common throughout the northern and eastern sections of the United States, as far west as Montana and as far south as northern Arkansas. Caterpillars overwintering in cornstalks and similar hiding places pupate in spring. Adult moths first appear in late spring and deposit clusters of white eggs on the undersides of leaves. The pinkish larvae that emerge feed on leaves and tassels. A "shot-hole" in leaves is a familiar sign of their presence. As caterpillars mature, they bore into main stalks and leave behind sawdust-filled holes. In addition to corn, they will also feed on tomatoes, potatoes, and peppers.
Remove or plow under old stalks after harvest. If borers have been a problem in the past, treat emerging ears and leaves with Bacillus thuringiensis (Bt) when the silk has partially emerged.
Photography by Keith Weller, USDA Agricultural Research Service, Bugwood.org
Article published on June 23, 2008.