1 Plant & Food Research Limited, Mt. Albert Research Centre Private Bag 92 169, Auckland 1142, NZ
2 School of Biological Sciences, University of Auckland, 261 Morrin Rd Tamaki Campus, Auckland 1142
Polistes chinensis nests were introduced to kiwifruit orchards as a proxy for a biological control agent aimed at controlling pest leafroller species. The aim was to monitor the impact of this generalist predator on other species in the kiwifruit orchard habitat. The nests were introduced to 5 organic orchards and 5 IPM orchards, as the invertebrate assemblages in orchards under these two different management systems had been found to differ significantly. The nests were monitored for their growth and survival, and prey items were collected from the wasps for identification. PCR analysis of the CO1 gene of the prey items revealed the wasps were consuming a similar range of prey to those found in studies of other New Zealand or overseas habitats. Prey items were primarily Lepidoptera, including the pest Epiphyas postvittana, but also included some predatory species. The populations of 50 non-target species were also monitored in the orchards in an attempt to detect population impacts from the wasps. The results may have implications for the use of generalist predators and parasitoids as augmentative biological control agents, or the encouragement of these species in conservation biological control programmes.