General Information

Common name: Cabbage head caterpillar
Scientific name: Crocidolomia pavonana, C. binotalisia, C. binotalis
Lepidoptera:Pyralidae

Synonyms: Cabbage caterpillar, Cabbage cluster caterpillar, CHC, Greater cabbage moth, Large cabbage-heart caterpillar, Leaf webber, Mustard leaf webber, Webworm (CABI, 2000), Croci (CIIFAD, 1995).

Host plants

Cabbage, cauliflower, Chinese cabbage, broccoli, kholrabi, radish, mustard, watercress, cotton, and on some beans

Distribution

Asia, parts of Africa and the Pacific islands, Queensland, Australia. This pest is not reported in Europe and the Americas.

Damage

The cabbage plant has 'window-like' damage on its outer leaves. Larval damage during early head formation results in an aborted head or multiple heads. The larva bores holes on developing heads. A damaged developing head contains frass and fecal matters.

The growing tips of cauliflower seedlings or transplants are nibbled by the larvae which resulting in 'blindness'. The outer leaves of the transplants become skeletonized. Feeding damage causes a discoloration of curd. The larva bores holes on the flowers and eats the seeds and is found hiding beneath the curd.

Description

The eggs are laid in clusters and held together by gelatinous glue. An egg mass contains 30-40 eggs. The newly hatched egg mass is colored green and turns reddish-brown as it matures. The eggs are laid close to the midrib or on the veins at the lower surface of leaves. The egg development lasts for about 5-7 days.

The newly hatched larva is slender and greenish-yellow in color and has a dark-brown head and thorax. As the larva grows, its body becomes green and its head becomes brown with light patches, and then turns whitish with longitudinal stripes as it matures. A larva undergoes five instars. The early larval instar feeds in group and as it grows, it disperses moving from plant to plant. A mature larva measures 1.2-1.6 cm long.

The pupa is yellowish-green and turns dark-brown as it grows. The pupa is enclosed in a silken cocoon. Pupation takes place in the soil, 2-6 cm below the soil surface.

The adult has a black thorax and a reddish-brown abdomen. The male has a thicker tuft of hairs along the costal margin near the base of the forewing than that of the female. The female has a curved ovipositor for reproduction. A female can lay 2-10 egg masses. The adult is a weak flier.