Three major primary parasitoids of the diamondback moth, Plutella xylostella (L.), are found in the Cameron Highlands, Malaysia. Cotesia plutellae (Kurdjumov) was discovered in the early 1970s, Diadegma semiclausum (Hellén) and Diadromus collaris (Gravenhorst) were introduced in the mid 1970s from New Zealand and Australia. Field studies in the early 1980s showed that C. plutellae was the domin...