Cabbage caterpillar

Crocidolomia pavonana (F.)

Lepidoptera: Pyralidae

The cabbage caterpillar belongs to the family Pyralidae and is distributed in tropical and subtropical regions worldwide.

Host plants and damage

Cabbage caterpillar is primarily a pest of crucifers. Economically important hosts are Brassica oleracea var. carpita (cabbage), Brassica oleracea var. botrytis (cauliflower), Brassica rapa ssp. chinensis (Chinese cabbage), and Raphanus sativus (radish).

For the first 4-5 days from hatching, small larvae feed on the underside of the leaf, creating window-like damage. After this they bore to growing center and eat complete leaves. Mainly the outer leaves will be skeletonized through intensive feeding. Larvae sometimes hide in leaves webbed together. Larvae bore holes and damage pods, and consume seeds. All plant growth stages are affected by cabbage caterpillar feeding.

Morphology & biology

Eggs are laid in clusters and are held together by gelatinous glue. Egg masses of 10-300 eggs are green initially, and then become red-brown after two or three days. Larvae hatch after 5-7 days.

First instar larvae are slender. Head and thorax are dark brown and the body is green-yellow in color. The second instar is green and the head is brown with light patches. The late larval instars are characterized by white longitudinal stripes, three dorsal and one on each side. These stripes disappear only when larvae are close to pupation. All abdominal segments have tubercles. Mature larvae measure 12-25 mm in length and are 1.5-2.0 mm wide.

Pupation takes place in a silken cocoon in the soil. The pupal period is 11-13 days.

Adults emerge at night. They have a black thorax and a red-brown abdomen. The male is distinguished from the female by the presence of thick hairs near the base of the forewing. The female moths have a curved ovipositor. The wingspan for female moths is 22-25 mm and for males, 20-25 mm. In both males and females is a variation in their markings on the cream background of the forewings.

Adult moths can live as long as 30 days and lay as 10 or more egg clusters.

Monitoring

The egg clusters can generally be seen on undersides of leaves. They are often laid near the veins. Webbing of leaves together with leaf damage indicates presence of larvae. Search for the larvae mainly on undersides of outer leaves.

Window-like feeding can be an early sign for infestation but can be also caused by Plutella xylostella.

Pest management

Rainfall acts as a major mortality factor. Therefore cabbage caterpillar is only important during dry season.

Biological control

Several Hymenopteran parasitoids such as Apanteles stantoni Ashmead, Trichogramma chilonis Ishii, and Cardiochiles sp. have been identified, but none of them was able to control the cabbage caterpillar effective.

Cultural control

Mustard, is used successful as a trap crop in cabbage fields in India.

Mechanical control

In Indonesia hand-picking of egg masses and larval clusters of cabbage caterpillars reduced population densities significantly.

Chemical Control

Most effective are spray programs, which assure insecticide contact with young larvae before they bore into the growing point of the plant.

Spray systemic insecticides at first appearance or when 3 % new damage on the head is found, is reported to be an effective alternative to fixed spray programs.

It is reported that commercial neem formulations and crude neem extracts offered adequate protection against this pest.

Spot spraying with Bacillus thuringiensis on only those plants with visible damage is reported to be successful.

Cabbage caterpillar has not demonstrated resistance to any insecticide employed for its management.