Cabbage Worms
On this page:
- Cabbage Looper—Trichoplusia ni
- Diamond Back Moth—Plutella xylostella
- Imported Cabbageworm—Pieris rapae
Three caterpillars can be voracious pests of cabbage, broccoli and other cole crops*. If allowed to become numerous they can completely defoliate plants. Minor infestations make plants look unsightly and can cause reduced yields and increased decay.
In addition to cole crops, the cabbage looper may also feed on lettuce, soybeans, tomatoes and some annual flowers.
(*Brassica is a genus of plants in the Brassicaceae family. Crops from this family are sometimes called cole crops, which comes from the Latin for stem or cabbage. Vegetables of this family are called cruciferous vegetables or crucifers because the four petals of their flowers resemble a cross. Brassicas, cole crops, and crucifers are all terms refering to cabbage, broccoli, cauliflower, Brussels sprout, turnip, kale, radish, rutabaga, collards and the like.)
Cabbage Looper—Trichoplusia ni
The cabbage looper larvae grow to about 2 inches, and are light green with a few white or pale yellow stripes. They move with a characteristic "looping" motion similar to inchworms.
Adult moths are mottled grayish brown with a 1 1/2 inch wing span. Each forewing is marked near its center with a pair of silver markings.
Larvae eat large irregular holes in the outer leaves of cabbage plants, sometimes eating into the head of cabbages. Heavy infestations result in skeletonized plants as all but the leaf veins are usually eaten.
Diamondback Moth—Plutella xylostella
Diamondback moth larvae are 1/4 to 1/3 inch long, tapered at both ends, pale yellowish-green, with fine, scattered black hairs over the body and a black head. They wriggle rapidly when disturbed, often dropping from the plant and hanging by a silk-like thread.
The adult is a grayish-brown moth with narrow front wings, fringed hind wings and a wing span of about 3/4 inch. When at rest the wings come together to form a line of white or pale yellow diamonds down the middle of the back.
Larvae feed on all plant parts; they eat small holes in leaves and buds, but prefer the undersides of older leaves, leaving "shothole" type damage.
Imported Cabbageworm—Pieris rapae
The imported cabbageworm larvae is velvety green, about 1 inch long, and tends to be sluggish. They feed and rest on the underside of leaves.
The adult of the cabbageworm is an off-white butterfly with one or two grayish-black spots per wing and a wing span of about 2 inches.
Larvae feed on foliage and can reduce mature plants to stems and veins. They prefer leafy foliage, but will burrow into the heads of broccoli and cabbage. Fecal pellets can be found between the leaves.
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Identification and Control Information
- Pest Management Fact Sheet: Imported Cabbageworm—University of Maine Cooperative Extension
- Caterpillar Pests of Cole Crops in Home Gardens (PDF)—University of Minnesota Extension Service
- Insects of Crucifers: Cabbage Looper (PDF)—Cooperative Extension New York State, Cornell University
- Wisconsin Garden Facts: Cabbage Looper (PDF)—University of Wisconsin-Extension
- Insects of Crucifers: Diamondback Moth (PDF)—Cooperative Extension New York State, Cornell University
- Insect Pests of the Home Garden Fact Sheet: Diamondback Moth (PDF)—New Jersey Rutgers Cooperative Research & Extension
- Imported Cabbageworm (PDF)—Insect Diagnostic Laboratory Cornell University
[Photos, left to right: Alton N. Sparks, Jr., University of Georgia, Bugwood.org; Keith Naylor, Bugwood.org; David Riley, University of Georgia, Bugwood.org; Russ Ottens, University of Georgia, Bugwood.org; Russ Ottens, University of Georgia, Bugwood.org; Alton N. Sparks, Jr., University of Georgia, Bugwood.org; Russ Ottens, University of Georgia, Bugwood.org; Whitney Cranshaw, Colorado State University, Bugwood.org; Whitney Cranshaw, Colorado State University, Bugwood.org]