NC State Extension Publications

Description and Biology

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Trichoplusia ni is called the cabbage looper because it is a fairly predictable pest of cabbage and because the caterpillar is an inchworm that loops to bring the hind end forward as it crawls about. The worms are about 1/16 inch long when they hatch. As the larvae grow, they become light green with two white stripes on top and two wider white stripes down each side. The markings become less distinct in the last instar. The body tapers toward the head and is about 1.5 inches long when full grown. Cabbage loopers pupate in a gauzy, transparent cocoon on the plant (not in the soil the way many other moth caterpillars do). The adult is a dark, mottled moth with a conspicuous, silvery figure 8 on each forewing. It's wingspan is about 1.5 inches. The moths fly primarily at night. Females lay about 350 eggs one at a time (not in masses). In North Carolina, there are five to six generations per year, mostly on crucifers.

The cabbage looper feeding on kalanchoe.

The cabbage looper feeding on kalanchoe.

The cabbage looper's cocoon is flimsy and transparent.

The cabbage looper's cocoon is flimsy and transparent.

Cabbage looper moths fly primarily at night.

Cabbage looper moths fly primarily at night.

Host Plants

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The cabbage looper feeds on most plants in the cabbage family including allysum, flowering kale, ornamental cabbage, and stock, as well as geraniums, mums, kalanchoes and almost every other ornamental plant! It is called the cabbage looper because it is a fairly predictable pest of the vegetable cabbage and related plants. Lettuce, spinach, beet, pea, celery, potato, cotton, soybean, tomato, and tobacco are other plants attacked by cabbage loopers. The caterpillars devour leaves and drop frass, which further disfigures plants.

Residential Recommendation

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A high degree of natural control by predators and parasites usually keeps cabbage looper populations under control. A polyhedral virus disease seems to be a key factor in overall population suppression. Remay or some other light weight row crop cover can also be used to exclude cabbage looper moths in the right location (the vegetable garden, not a front yard flower garden!). The cabbage looper is not particularly resistant to pesticides so Sevin, Orthene or some other contact insecticide should give adequate control on ornamentals.

References

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For assistance with a specific problem, contact your local Cooperative Extension Center

The Factsheet has not been peer reviewed.

Author

Professor Emeritus
Entomology and Plant Pathology

Publication date: June 27, 2013
Revised: Sept. 11, 2019

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