This striped, green, brown, and yellow caterpillar, also known as the tomato fruitworm and the cotton bollworm, attacks a variety of crops but is most destructive to sweet corn. After feeding on silk, the corn earworm enters the ear and feeds on the kernels.
To protect your crop, apply a few drops of mineral oil to the silk of each ear as soon as it has wilted and before it dries out. You may find that long, tight-husked varieties, such as Silver Cross Bantam, Country Gentleman, and Dixie 18, are more pest resistant.
Corn earworms can be controlled by spraying with carbaryl or diazinon when the ears appear and ever y5 days thereafter until the silking period ends when the cornsilk tassles turn brown and wither. These same insecticides are also effective against the European corn borer, a pest that eats into corn stems.