Pest Information

Common name: Cabbage looper
Scientific name: Trichoplusia ni
Lepidoptera:Noctuidae

Host plants

Cabbage, collards, broccoli, cauliflower, celery, pea, potato, spinach, lettuce, parsley, tomato, tobacco, cucumber, cotton, soybean

Distribution

Asia, Africa, Central America, eastern coast of USA. T. ni is widely distributed but is usually considered to be of tropical or subtropical origin.

Damage

Larvae feed primarily on leaves causing irregular, rugged holes, bore through the heads, and contaminate heads and leaves with their frass (excreta). Their frass stain cauliflower heads and make broccoli heads unmarketable. Large larvae can burrow through 3-6 layers of tightly wrapped head leaves in cabbage. Plants can be severely defoliated and stunted, producing no head or be unfit for consumption. Sometimes, they damage the seedlings, but heavy injury usually occurs after heading.

Description

The egg is very small and bowl-shaped with a flat side, yellowish to greenish-white in color, and found singly lying on the leaves.

The larva is light green and about 3-4 cm long when fully developed. It has 3 pairs of slender legs near the head and 3 pairs of thickened prolegs on the abdomen. It moves by arching its back to form a loop and then projecting the front section of the body forward. It usually feeds on the leaves and into the cabbage head.

The pupa is green or brown in color and is nearly 2 cm long. It is enclosed in a flimsy, silken cocoon. Pupation occurs in a folded webbed leaf or between two webbed leaves.

An adult is a grayish-brown moth and has a wingspan of about 3.3-3.8 cm. Each of the mottled and brown front wings which bears a small and silvery-spot that resembles like a figure 8. The hindwings are paler-brown. Adults are strong fliers and are primarily nocturnal. During the day the adults can be found resting in foliage or in crop debris. Moths feed on various wild and cultivated hosts where they obtain water and dissolved nutrients. A female moth can produce 300-1600 eggs.