At night, caterpillars feed on stems of vegetable and flower seedlings and transplants near the soil line, severing them or completely consuming small seedlings. During the day they rest below soil surface, curled beside plant stems.
Some species overwinter as pupae; adults emerge and lay eggs on grass or soil surface from mid-spring to early summer. Eggs hatch in 5 to 7 days, larvae feed on grass and other plants for 3 to 5 weeks, then pupate in soil. Adults emerge late summer to early fall. Other species overwinter as eggs that hatch during first warm days and feed on early seedlings. One generation per year; a late second generation may damage crops in warm fall weather.
Put collars made of paper, cardboard, or plastic around transplant stems at planting. Collars should be 3 or 4 inches tall; push collars into soil until about half of the collar is below soil level. One week before setting out plants, scatter moist bran mixed with BTK and molasses over surface of beds; apply parasitic nematodes to soil; dig around base of damaged transplants in the morning and destroy larvae hiding below soil surface; set out transplants later in the season to avoid damage.
Learn More: How to Make Cutworm Collars
Photo: Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org