University of Illinois Extension

University of Illinois Extension

Hort Answers

Insect Damage

Cabbage Looper
Trichoplusia ni

Cabbage looper
Cabbage looper
2 (1 = rare 5 = annual)
3 (1 = very little damage 5 = plants killed)
Cole crops


Cabbage looper caterpillars get their name from the way they push the center of the body up into a large loop when they move. Full-grown larvae are about 1 inch long. Cabbage looper adults are brown moths that fly at night.

The caterpillars eat holes in the leaves and heads of cabbage, broccoli, brussels sprouts, kale, collard, and kohlrabi.

Life Cycle

Do not overwinter in the Midwest. Migrate from the southern states in early summer through September. Pupates on the underside of the leaf in cocoons. There are 2-3 generations in the Midwest.

The use of insecticides on cole crops will be needed if more than 10 percent of the plants are attacked in the seedbed or when plants are near harvest. Higher percentages of attack are acceptable on growing plants. Treat greens if 5 percent or more are infested.

Related Resources
Home, Yard & Garden Pest Guide
Illinois Commercial Landscape and Turfgrass Pest Management Handbook
U of IL - Distance Diagnosis through Digital Imaging
U of IL - Plant Clinic