Identification

Loopers are green caterpillars with several white stripes down their backs. They arch their backs as they crawl, this looping movement giving them their name. The most common looper is the cabbage looper, Trichoplusia ni. View similar looking species.

Life Cycle

Eggs are laid singly on undersides of older leaves; eggs are dome-shaped with ridges. The larvae occur primarily on the underside of leaves and are easily recognized by their habit of arching their backs. They feed mostly on mature foliage. The pupa is enclosed in a thin silk cocoon spun on the underside of mature leaves, in the crown of the plant, or in debris on the ground. Adults are moths.

Damage

Loopers eat irregular holes in leaves, most often older leaves. They may also bore holes in lettuce and cabbage heads or damage fruit.

Solutions

Handpick. Apply Bacillus thuringiensis or spinosad; they are effective against loopers, especially when caterpillars are small. Natural control by viral diseases, general predators, and parasites (Hyposoter, Copidosoma, Trichogramma) is often effective. Floating row covers can prevent egg laying.