Cabbage Loopers

Cabbage looper larvae are common summer garden pests.

Cabbage looper larva (Alton N. Sparks, Jr.) CC BY 3.0

Nocturnal brown moths (Trichoplusia ni) fly in at night and lay tiny hemispherical eggs, singly or in clusters, on upper and lower leaf surfaces. Adult moths live 10 to 12 days. Females can lay 300 to 600 eggs in that time. Two to ten days alter, pale white larvae emerge and begin feeding on the underside of leaves of cabbage, broccoli, and other members of the brassica family. As the loopers grow, they move to the upper side of leaves and feed heavily, leaving large ragged holes. They also feed on tomatoes, kale, radish, lima beans, lettuce, peas, peppers, beans, spinach, squash, sweet potatoes, watermelon, cucumbers, potatoes, thyme, and collard greens, leaving behind clumps of dark green droppings.

Cabbage looper description

​There are actually several different cabbage looper species, usually based on their favorite food. All cabbage looper larvae reach 1-1/2 inches long and end up pale green. They start out white but, as they feed, they turn green. They move in a classic ‘looping’ inchworm motion. The adult moth is brown.

Adult cabbage looper moth (Calibas) Public Domain

Cabbage looper control

Unlike other inchworm larval forms, cabbage loopers are resistant to Bacillus thuringiensis (Bt). Luckily, they have many natural predators in the form of big-eyed bugs and parasitic wasps. Avoiding the use of broad spectrum pesticides can help these beneficial insects protect your crops. Hand-picking cabbage loopers can also reduce damage.