Cabbage Looper
Trichoplusia ni (Hubner), Noctuidae, LEPIDOPTERA

DESCRIPTION

Adult - This grayish-brown moth has a wingspan of approximately 38 mm. Each of the mottled, brown, front wings bears a small, silvery spot resembling a figure 8. The hind wings are a paler brown.

Egg - The dome-shaped, greenish-white egg is slightly smaller than a pinhead.

Larva - About 40 mm long when fully developed, the light green larva has three pairs of slender legs near the head and three pairs of thickened prolegs on the abdomen. The body tapers from the rear to a small head and is generally humped up when at rest or moving.

Pupa - The green or brown pupa is nearly 19 mm long and enclosed in a flimsy, silken cocoon.

BIOLOGY

Distribution - The cabbage looper is found from Canada to Mexico. In the U.S., this insect is a pest primarily in the South.

Host Plants - Host plants include all of the plants of the cabbage family -- cabbage, collards, etc. Also attached are lettuce, spinach, beet, pea, celery, potato, cotton, soybean, tomato, tobacco, and certain flower species.

Damage - An occasional pest of tobacco, the cabbage looper leaves ragged holes as it feeds on tobacco leaves.

Life History - Cabbage loopers overwinter as pupae attached to host plant foliage which has fallen to the ground. The night-flying moths appear in May and lay eggs (up to 350 per moth) singly on cabbage, collards, and other plants. The eggs hatch in about three days, depending on temperature. The loopers feed on leaves for two to four weeks before spinning cocoons and pupating. Ten days to two weeks later a new generation of moths emerges. In North Carolina, there are five to six generations per year, mostly on crucifers.

CONTROL

There is apparently a high degree of natural control of the cabbage looper by predators and parasites. Also a polyhedral virus disease seems to be a key factor in population changes of the cabbage looper. Insecticides are available to control the cabbage looper when it becomes abundant. Treatment is advised when 10 percent of the plants are affected. For specific chemical recommendations, consult the current North Carolina Agricultural Chemicals Manual.