Cutworm

• Seedlings or transplants cut off at or just below the soil surface — the stem cleanly severed
• The plant topples overnight with no other visible symptoms
• Plump, dull gray or brown caterpillars found curled in the soil near the base of damaged plants
• Larger plants may show climbing cutworm feeding — ragged holes in leaves and fruit

Cutworm moths lay eggs on grass and weeds in late summer. Larvae overwinter in the soil and become active as soil warms in spring. They feed at night and hide underground during the day, which is why they are rarely seen. Most cutting damage occurs in May and June when transplants are set out. Adults can also fly and lay new egg masses during summer.

1. 01Place physical collars around transplant stems — a toilet paper roll or cut plastic cup pushed 1 inch into the soil works well
2. 02Dig around cut plants to find and destroy the culprit cutworm, which typically stays within a few inches of the damage
3. 03Till the bed a week before transplanting to expose larvae and pupae to birds and drying
4. 04Apply Bacillus thuringiensis var. kurstaki (Bt) or spinosad as a soil drench around plant bases in the evening
5. 05Diatomaceous earth applied around stem bases may deter surface movement
6. 06Remove and destroy grass and weed growth around the garden perimeter — egg-laying habitat

If cutworm damage is extensive across a new bed and physical collars haven't been enough, an extension office can help identify whether black cutworm (Agrotis ipsilon) — a migratory species — is involved, which can change the timing of management.

• Cutworms in the Garden— University of Maryland Extension
• Cutworms— Penn State Extension