Some cutworm caterpillars cut off young plants, and stunt or kill taller plants by feeding on underground roots and stems. Corn, peppers, tomatoes and beans seem to be their favorite food, but they will attack many kinds of plants. The larvae are nocturnal, hiding in the soil during daylight hours except on dark, wet days.

Cutworms overwinter in the late larval or pupal stage. The brownish gray moths may appear shortly after warm weather arrives. The moths are attracted to weedy fields, especially if mustard or quackgrass is present. They also may lay their eggs in weedy, overgrown gardens before spring planting.

Once gardens are planted, the young larvae feed on small roots until they are half grown, or about 3/4 inches long. After that, they become more likely to cut off plants at ground level. They may drag part of the plant into the soil, where they hide during the day. The larvae can usually be found hiding in the soil in the daytime near a cut plant. The thick-bodied larvae are normally dark colored and curl up when disturbed.

Management

The most important means of controlling cutworms is to avoid planting in soil that was sod covered in the previous year or two and to keep crop areas as weed-free as possible, especially in September, October and in spring. This discourages the moths from laying their eggs in the garden in early fall as well as in the spring. Using compost instead of green manure will also discourage infestation. Fall plowing and tillage may help destroy or expose overwintering pupae.

Climbing cutworms can be handpicked off the plants well after dark.  Placing collars around stems, pushing the collars 1 inch into the soil, or wrapping stems with aluminum foil protects young plants. The effectiveness of mulch as a control depends on the material used and how it is applied. Similarly, the effectiveness of insecticides in controlling cutworms depends on when, where and how they are applied.

Carbaryl (Sevin) or rotenone sprays or dusts are applied to the base of plants and the surrounding soil. Bait formulations have special advantages: direct toxic effect on caterpillars and attractiveness.