Facts, Identification & Control
The adult cabbage looper moth wingspan is about 1 ½ inches long with gray-brown wings with a silver or white spot that looks like a “V”, figure “8” or a “Y” on the front wings. The larva is green and has characteristic white lines on its top and sides. As the name looper suggests, the larva moves by using a looping motion of arching its back and then straightening out its body. The pupal stage is found on the bottom of the host plants’ leaves or in the soil and plant debris. Cabbage loopers are serious agricultural pests, but the homeowner may also experience problems with this insect feeding on their garden plants.
Behavior, Diet and Habits
Cabbage loopers overwinter in the pupal stage and the adult moth emerges in the spring. Adult moths are usually active at dusk or after dark. The larvae feed on their host plants for three to four weeks, and mature adult female moths will lay up to several hundred eggs on the surface of the host plant’s leaves. Their common host plants are cabbage, collards, turnips and broccoli, but they will also feed on numerous commercial and home garden plants like lettuce, celery, beets, spinach, tomatoes or potatoes. Cabbage looper damage is recognized by the early larval stage damage to the lower surface of the leaf, while the later larval stages eat holes in the leaves. Larval feeding is also recognized by a collection of moist, sticky fecal material the larvae deposit while feeding.
The first step in cabbage looper control is to contact your pest management professional and obtain an accurate identification. Once you know what is causing the problem, your pest management professional can provide advice and recommendations that will help resolve the problem and will recommend an integrated pest management (IPM) program. If the IPM program includes using insecticides, always ask your pest management professional for assistance in selecting and safely using these products. Some useful components of such a program for the homeowner include:
- Removing larvae or egg masses by hand.
- Removing plant debris after harvest. Since the cabbage looper pupae may overwinter in garden debris, clean up and till your garden each fall.
- Plant flowers that can attract cabbage looper predators. Knowledgeable experts at your garden center or nursery can help select the right plants.
- Spraying Bt (Bacillus thuringiensis), a bacterial insecticide that helps control the cabbage looper. Contact your pest management professional before using this or any other insecticide product.
- If possible, choose garden plants that are cabbage looper tolerant.
- Use row covers to prevent adult moths from laying eggs on garden plants. Make sure that garden plants are not already infested by cabbage loopers or their eggs before covering the plants.