Also known as the tomato fruitworm and cotton bollworm, this caterpillar changes appearance markedly as it grows. Young Corn Earworms are tiny and white, with black heads; older ones are 1 1/2 inches long and green to nearly black in color, with lengthwise stripes and stubby spines along their backs. Finding one of these pests in an ear of corn is dismaying–but the damage is modest, and the ear can be salvaged by cutting off the spoiled tip.
Target: Corn, tomatoes, and other vegetables.
Damage: Caterpillars and eggs are found in silk and tip kernels of ripening corn; tomatoes may be tunneled.
Life cycle: In spring, moths lay domed, ridged, whitish eggs singly on silks or leaf undersides. Caterpillars hatch and feed for several weeks, then pupate in the soil. There are up to seven generations a year.
Notes: Plant tight-husked corn varieties; or put a clothes pin or rubber band on tip of husk. Place a dropperful of mineral oil in tip of ear when silks have withered but before they turn brown. Apply Bt or inject nematodes into husk during silking.