Insect Pests

Full-grown larvae are about one inch long with a dark brown head and a white to pink body marked with several small black spots along the top. - Clemson University USDA Cooperative Extension Slide Series, www.insectimages.org

European corn borers are caterpillars that bore through the insides of corn stalks and occasionally also attack beans, beets, celery, peppers, and potatoes. Although they are hidden inside the plant, you will know their presence by the broken stalks, sawdust castings outside the entry holes, or broken tassels. The caterpillars also burrow up into the base of corn ears, sometimes causing them to fall. Once they are inside the plant, there is nothing you can do to kill the pests. In many cases, gardeners just learn to tolerate them. They are present throughout the US except west of the Rockies.

Corn borer moths appear in spring to lay eggs on the undersides of the leaves, where the eggs are protected from spray. The best way to prevent them is to clean up the garden, because they over-winter inside old stalks left lying around. If you choose to spray, use oil or pyrethin spray, being sure to coat the undersides of the leaves thoroughly. Your county Extension agent may also recommend another product approved in your state.