Corn Earworm
Pest · Commonly affects: Sweet corn, Tomatoes, Peppers, Snap beans, Okra, Lettuce
The corn earworm (Helicoverpa zea) is a native moth whose caterpillar is one of the most damaging pests of sweet corn in the United States, and it also feeds on tomatoes, peppers, and beans. Gardeners care because a single larva can ruin the tip of an ear or bore into a ripening fruit, and the pest is widespread, moving north each season as adult moths migrate.
How to identify it
Look for a fat caterpillar up to about 1.5 inches long, ranging in color from pale green or pink to brown, with light and dark lengthwise stripes and a distinctly patterned tan head. On corn you will usually find one larva feeding at the ear tip, surrounded by moist, sawdust-like droppings called frass; on tomatoes and peppers the larva bores into the fruit near the stem. The adult is a tan to olive moth with a dark spot near the center of each forewing, most active at dusk and night.
Damage
On sweet corn the caterpillar chews through the silks and then eats the developing kernels at the tip, which spoils the ear and opens the wound to rot and secondary molds. On tomatoes, peppers, and beans it tunnels into the fruit and pods, leaving holes packed with frass that make the produce inedible and prone to decay.
Prevention
Rotate corn and tomato-family crops so this year's planting is not next to last year's, and clean up and destroy or deep-bury crop residue after harvest since the pest overwinters as a pupa in the soil. Choose sweet corn varieties described as having long, tight husks that extend well past the ear tip, since a snug husk makes it harder for young larvae to reach the kernels. Planting early and avoiding late successions can help you harvest before local moth numbers peak, and keeping plants evenly watered and healthy helps them tolerate the feeding that does occur.
How to manage it
Scout ears and fruit regularly and handpick the caterpillars you find, dropping them into soapy water. A classic home-garden trick is to place a few drops of mineral or vegetable oil at the silk end of each corn ear a few days after the silks appear, which discourages larvae from moving into the tip. Floating row covers can keep egg-laying moths off tomatoes and peppers before they set fruit, and you can encourage natural enemies such as parasitic wasps, lacewings, and predatory bugs by growing small-flowered plants and avoiding broad sprays; remove and dispose of any infested ears or fruit promptly so the larvae do not complete development in your garden.
General guidance for US home gardens, focused on prevention and non-chemical control. For a confirmed diagnosis and options specific to your area, contact your local Cooperative Extension office. Page updated Aug 4, 2026.