Corn earworm, also called bollworm, ranks among the worst insect pests in the United States. Most corn earworms are greenish-brown with dark stripes. They measure about 11/2 inches (4 centimeters) long. The adult is a grayish-brown moth.
On corn, the moths usually lay their eggs on the silk. The eggs hatch in two to eight days. As far north as Kentucky, three broods of the insects appear each year–in June, July, and August. Farther north, two broods are normal. To the south, as many as five broods may occur. Corn earworms also attack cotton, tomatoes, alfalfa, beans, and other crops. The corn earworm is called the bollworm when it attacks cotton bolls. Farmers plow under all crop remains and use crop varieties resistant to corn earworms to control the insects. Insecticides also may be needed to protect some crops.
