Cutworms
Black cutworm, Agrotis ipsilon (Hufnagel)
Granulate cutworm, Feltia subterranea (Fabricius)
Variegated cutworm, Peridroma saucia (Hubner)
Noctuidae, LEPIDOPTERA

DESCRIPTION

Adult - Adult black cutworm moths have dark brown forewings, white hind wings, and a wing expanse of 38 to 51 mm. Adult granulate cutworm moths have yellowish-brown forewings and a wingspan of 38 to 45 mm. The variegated cutworm moths may be yellowish or brownish with a wingspan of 38 to 50 mm.

Egg - Cutworm eggs are white -- laid singly or in small clusters. Variegated cutworm eggs are generally laid in elongate patches.

Larva - Black cutworm larvae are dark greasy-gray to black, with a pale yellow line down the center of the back and three yellow lines along each side. Sometimes, however, these yellow lines are not distinct. The larvae are 38 to 45 mm long when fully developed and the skin is covered with convex, black granules. Granulate cutworm larvae are dusty brown with rough, granulated skin and up to 38 mm in length. Variegated cutworm larvae have a distinct, pale yellow dot on the mid-dorsal line of at least the first four abdominal segments. About 50 mm long when fully developed, they are a pale, dirty brown in color.

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

BIOLOGY

Distribution - Cutworms are cosmopolitan in their distribution and are common in Canada and the United States. The black cutworm is more abundant in the northern portions of its range, while the granulate cutworm is more abundant southward. In North Carolina, cutworms are generally more of a problem in the Coastal Plain.

Host Plants - Cutworms attack many vegetable crops, grasses, and field crops such as tobacco, cotton, corn, and peanuts.

Damage - Several species of cutworms may injure tobacco in plant beds and newly set plants in the field. Larvae hide curled up in the soil by day and at night cut off young plants near the ground and feed on the foliage. The black cutworm is one of the most destructive cutworms. One larva cuts off a plant, moves to other plants and repeats the damage. Small populations can cause considerable injury, resulting in the need to replant. Granulate and variegated cutworms also sever seedlings, but the variegated cutworm may also climb tobacco plants and feed on the leaves. In North Carolina, granulate and black cutworms are the most common cutworms in tobacco plant beds.

Life History - Cutworms overwinter as larvae or pupae. In early spring, the overwintering larvae of some species become active and feed. 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. Pupation occurs in the soil. The number of 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.

CONTROL

Since extensive damage may occur in a short period of time, plant beds and newly set plants should be inspected frequently. An economic threshold of 5 percent injured plants has been established for cutworms infesting newly set or young plants (within 3 weeks after transplanting). A bait may be used in infested plant beds or in newly set fields. For control recommendations, consult the current North American Chemicals Manual.