Parasitism of lepidopteran larvae collected from vegetable crops and associated weeds at Pukekohe

Abstract

A weekly survey of lepidopteran larvae present on vegetable crops and associated weeds was undertaken at Pukekohe from December 2002 to June 2003 The polyphagous pests Thysanoplusia orichalcea (soybean looper) and Helicoverpa armigera (tomato fruitworm) were common on most species of plants and the brassica pests Plutella xylostella (diamondback moth) and Pieris rapae (white butterfly) were the other two species most commonly collected The accidentally introduced polyphagous parasitoid Meteorus pulchricornis was reared from all lepidopteran species collected except for P rapae Results indicate that M pulchricornis may be competitively displacing the important introduced specific parasitoid of H armigera Cotesia kazak with 89 of all parasitised H armigera larvae parasitised by M pulchricornis Cotesia rubecula an introduced solitary parasitoid of P rapae also appears to have displaced the earlier introduced Cotesia glomerata Three species of entomopathogenic fungi were isolated from various species of Lepidoptera