Corn earworm in sweet corn
Moths lay single eggs on fresh silk, and the larvae reach the ear tip within a day. Protection therefore means keeping the silks covered from the start of silking until they brown. Kentucky says control is impossible once larvae are inside the ear. For a few garden plants, UF/IFAS gives a non-spray option: 0.75–1.0 ml of mineral oil on the silks five to seven days after silking.
At a glance
- Damage
- Ear tips eaten and full of frass; holes in tomato fruit
- Type
- Chewing
- Settings
- Field, Garden
- Threshold
- Moth trap catches set spray intervals commercially (UMass, UKY); no garden threshold
- Ally
- Bacillus thuringiensis kurstaki
- Rate
- Label rate. DiPel DF lists corn earworm at 0.5–2 lb per acre on corn, repeated as the label directs; home Bt products may not list it
How to confirm it
In corn: pull back the husk at the tip and look for a caterpillar and moist frass among the eaten kernels, usually just one per ear. In tomato: a hole at the stem end of green fruit with a watery, frass-filled cavity. The larva is up to 1½–2 inches (4–5 cm), striped, and green, brown, pink or nearly black, with a rough texture from small spines.
Identification, lifecycle, degree days and every control option are on the full Corn earworm profile. Not sure it is this pest? Answer four questions about the damage.