Pests & diseases › Corn Earworm
Corn Earworm
Striped caterpillar feeding inside the tip of corn cobs. Also attacks tomatoes (called tomato fruitworm) and beans.
Symptoms
- Caterpillars feeding in the top inch or two of corn cobs
- Frass at the silk end of cobs
- Holes in tomato fruit (also corn earworms — same species)
- Damaged grains spoiling and going moldy
Lifecycle
Multiple generations. Migrates north each summer.
What to do
- Squeeze 5 drops of mineral oil onto silks 5–7 days after silks emerge — smothers eggs/larvae
- Bt spray on silks
- Cut off damaged cob tips — rest of cob still good
If it's bad
- Spinosad on silks
Stop it coming back
- Plant early-maturing varieties before main moth flights
- Resistant varieties: Country Gentleman, Silver Queen
Crops it goes for
Plan the plot, track every sowing, cook the harvest
Sowing reminders and harvest forecasts for your own frost dates, the Seed Tin, Scan Centre for any label or packet, and the Potty Mouth Garden Club. Free to start.