The cabbage or diamondback moth (Plutella xylostella) is usually the most numerous and smallest caterpillar found on brassica crops. This, together with their uniform colour and habit of vigorous wriggling and hanging by a silken thread when disturbed, readily distinguishes them from other caterpillars. Larvae are up to 10mm long and are pale green, cigar-shaped and wriggle violently when disturbed. Moths are 8-10mm long, are grey-brown with a medial white stripe which appears as a series of diamonds when the wings are folded. Larvae chew on leaves resulting in ‘windows’ or holes and severe defoliation can mean reduced yield and quality. Larvae may also feed on pods.