Corn Earworm / Tomato Fruitworm

• Holes at the tips of corn ears, with frass (dark excrement) visible under silks
• Large striped caterpillar (green, brown, or pink) eating kernels from the tip downward
• On tomatoes: entry holes in fruit, often near the stem; hollowed-out fruit with larva inside
• On peppers: small bore holes, internal feeding damage, secondary rot at wound sites
• On beans, cotton, and many other crops: the same caterpillar is also called the cotton bollworm

Adults are night-flying moths that migrate north from the southern US each year. Females lay eggs singly on corn silks, tomato leaves, or pepper calyxes. Larvae hatch and immediately bore in — once inside, they are nearly impossible to treat. Multiple generations per year in warm climates; typically one or two generations at northern latitudes. Overwinters as pupae in the soil in regions where winters are mild.

1. 01Plant early-maturing corn varieties so ears silk out before earworm populations peak
2. 02Apply a few drops of mineral oil + Bt (Bacillus thuringiensis) or spinosad to the silk channel of each ear 4–7 days after silks emerge — before larvae bore in
3. 03On tomato and pepper: check developing fruit daily and remove any with entry holes; destroy (do not compost)
4. 04Row cover until tasseling; remove when pollination begins
5. 05Encourage Trichogramma wasps and lady beetles — they parasitize eggs and suppress populations
6. 06Fall tillage exposes pupae to cold and predators in regions where the pest overwinters locally

If you see severe damage across multiple crops at once (corn + tomato + pepper), contact extension — they can advise on timing of Bt or spinosad applications for your region and crop mix.

• Corn Earworm— University of Minnesota Extension
• Tomato Fruitworm— Clemson Cooperative Extension