Widespread distribution. Asia, Africa, Oceania. On members of the brassica family - broccoli, cabbage, cauliflower, Chinese cabbage, mustard and radish.
Egg masses yellow. Young larvae feed together often on the 'head'. Larger larvae with long hairs, yellow lines along the back and brown heads.
Larvae feed under silk webbing at the plant centre.
Cultural control: inspect nurseries and crops frequently: remove egg masses and/or larvae; plant far from old crops; trap crops, e.g., mustards or Chinese cabbage (Bok Choy), but destroy trap crop before insects hatch.
Chemical control: in household plots, PDPs to safeguard natural enemies (chillies, neem, derris, pyrethrum); in commercial plots, grow under nets; use Bt (Bacillus thuringiensis) sprays against caterpillars when young.