Attempted biological control of social wasps, Vespula spp., (Hymenoptera: Vespidae) with Sphecophaga vesparum (Curtis) (Hymenoptera : Ichneumonidae) in New Zealand

Abstract

During 1979, cocoons of the ichneumonid Sphecophaga vesparum hurra (Cresson), a parasitoid of some Vespinae, were imported from Washington State, USA to New Zealand. Two adults and four cocoons raised in quarantine on Vespula germanica (F.), the German wasp, were field released, but there was no evidence of establishment. Subsequent imports of S. vesparum vesparum (Curtis) from Europe were propagated mainly on the recently immigrant V. vulgaris (L.), the Common wasp. Thirteen generations of S. v. vesparum were raised by July 1985, and all stages of the parasitoid were released into wasp nests in Canterbury. Six of seven V. vulgaris nests and three of six V. germanica nests were parasitised. Although releases occurred late in the growth cycle of nests, at least one generation of parasitoids emerged in four V vulgaris nests and one V. germanica nest. One of the V. vulgaris nests probably developed two generations of parasitoids. Parasitoid numbers in this nest increased approximately eight-fold.