Worldwide distribution. On cabbage, cucumber, potato, daisy, legume plant families, and more. An important moth pest.
Early larvae make 'windows' in leaves; later larvae make holes or defoliate plants.
Eggs laid on underside of leaves; larvae blue-green, with white lines along body, up to 40 mm long. Move by looping. Pupae in silken cocoons in soil or on leaves. Adults, dark grey-brown, with silvery patches on forewings and two white spots, wingspan 30-40 mm, and bunched hairs like horns on head.
Natural enemies: parasitoids give good control, and nuclear polyhedrosis virus effective.
Cultural control: inspect nurseries and crops regularly; remove larvae by hand; use trap crops, e.g., mustards or Chinese cabbage (Bok Choy), but destroy trap crop before insects hatch.
Chemical control: in household plots, use PDPs (chillies, neem, derris, or pyrethrum); in commercial plots, grow under nets; use Bt (Bacillus thuringiensis) sprays against caterpillars when young.