Cabbage head caterpillar’s Indonesian name is “ulat krop” and its scientific name is Crocidolomia pavonana.
Cabbage head caterpillar moths are creamy-brown and about 18mm long. At rest, adults hold their wings at an angle and do not sit flat.
Moths are active only at night and are rarely seen during the day. They can infest crops from early growth through to harvest.
Cabbage head caterpillar moths lay eggs overlapping each other in clusters of 10 to 140 eggs. Egg clusters are laid on the underside of leaves.
Newly laid eggs are pale green then turn bright yellow and develop an orange crescent before turning dark brown just before hatching. These egg clusters differ from those of cluster caterpillar (Spodoptera) which are covered with fine scales.
Newly hatched cabbage head caterpillar larvae are about 2mm long, hairy and look ‘wet’. They feed in groups.
Older larvae are light green and hairy and have white or pale green stripes along their backs. Larvae cover the surface of plants with thick silken webbing and feed beneath it.
Fully developed larvae are 20mm long and when mature, burrow into the soil and form shiny brown cocoons.