The European corn borer is a flesh-colored worm with a reddish or blackish head and two distinct light brown spots on the top of each abdominal segment. It is one of the major corn pests and occurs in two or more generations throughout the season. Mature larvae overwinter, pupate in the spring and emerge as moths in June. Females lay eggs on the most advanced corn available.
Young borers seek protection in midribs, behind leaf sheaths, and in the whorls.
As tassels emerge, the borers crawl behind the leaf sheaths and imbed in the stalk. There they mature, pupate, and emerge as moths to lay eggs for a second generation on late-planted corn where the borers feed in the stalks, ear shanks, and ears. A third generation may occur in the southern third of Illinois. As the worm grows it leaves this area and begins to tunnel in leaf midribs and sheaths. The second generation is present on corn after the tassel has emerged.