Cutworms
Black cutworm, Agrotis ipsilon (Hufnagel); Spotted cutworm, Amathes c-nigrum (Linnaeus); Variegated cutworm, Peridroma saucia (Hubner), Noctuidae, LEPIDOPTERA


DESCRIPTION

Adult - Black and variegated cutworm moths have wingspans of 38 to 51 mm. The forewings of black cutworm moths are dark with three black dashes and a white splotch near the tip of each wing. Forewings of variegated cutworm moths are basically yellowish or light brown with pale mottled designs. Spotted cutworm moths have brown forewings, often tinged red or purple, with a pinkish trianglular spot on the anterior margin and a moon-shaped spot near the center of each wing. The wingspan is only 30 to 40 mm. The hind wings of all three species are pale gray or off white with dark veins.

Egg - White at first, the round eggs have a diameter of 0.5 to 0.7 mm and may become slightly tinted before hatching.

Larva - Black cutworms are greasy-looking, gray to black caterpillars up to 46 mm long. As long as 38 mm when fully grown, spotted cutworms have a pale brown or gray body with black wedge-shaped spots on each segment of the posterior half of the body. The spots increase in size toward the tip of the abdomen. About 50 mm long when mature, variegated cutworms are pale brown with a distinct yellow dot on each segment down the center of the back.

Pupa - Cutworm pupae are bout 20 mm in length and dark brown or mahogany in color.


BIOLOGY

Distribution - Cutworms are cosmopolitan in their distribution and are common throughout most areas of Canada and the U.S. The spotted cutworm, common in northern, central, and Gulf states, has a scattered distribution from North Carolina to Florida.

Host Plants - As general feeders, most cutworms attack a wide range of plants. Some common vegetable hosts include asparagus, bean, cabbage and other crucifers, carrot, celery, corn, lettuce, pea, pepper, potato, rhubarb, and tomato.

Damage - Young cutworms climb plants and feed on spears and ferns of asparagus. The mature cutworm, however, are sluggish, nocturnal, and soil burrowing. They typically sever plant stems during the night and hide in soil near the base of plants during the day.

Life History - Cutworms overwinter as larvae or pupae, depending on the species. In early spring, overwintering larvae of some species become active, feed, and complete their development. In other cases, moths emerge from overwintering pupae and lay eggs on host plants or other vegetation. Therefore, depending on the species, damaging cutworms found in spring may be overwintered larvae or new generation cutworms. Cutworms develop through five to eight larval instars (again depending upon the species).

Pupation occurs in the soil and lasts about 2 weeks for nonoverwintering pupae. Moths emerge and deposit 55 to several hundred eggs on host plants. The number of annual generations depends on latitude. Generally, there are two generations per year in Canada, four generations per year in North Carolina, and five to six generations per year in Florida. The spotted cutworm, however, produces only two generations per year throughout the U.S.


CONTROL

In small gardens, barriers around plants can prevent serious cutworm damage. By encircling individual plants with cardboard or metal "collars" pressed 2 to 3 cm (1 in) into the soil, gardeners put up "fences" the cutworms cannot cross. Such a method, however, is not practical for large acreages. Should cutworms become a problem, consult the N.C. Agricultural Extension Service for the latest recommendations.

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