The discovery and rearing of a parasitoid (Hymenoptera: Pteromalidae) associated with spotted wing drosophila, Drosophila suzukii, in Oregon and British Columbia

Adult pteromalids were reared from Drosophila suzukii (Diptera: Tephritidae) infested sweet cherries (Prunus avium) in Hood River, OR, and from infested sweet cherries and blackberries (Rufus spp.) in Summerland, British Columbia. The parasitoid discovered in Summerland was identified as Pachycrepoideus vindemmiae (Rondani). The parasitoid discovered in Hood River appears to be a morphospecies of P. vindemmiae and is awaiting species identification. In Summerland, the parasitoid was placed into rearing cages containing adult D. suzukii and infested cherries. Within a month, the increasing parasitoid population caused the D. suzukii colony to collapse. In Hood River, adult parasitoids were provided a food source (honey) and D. suzukii larvae. Parasitoids were observed ovipositing into D. suzukii puparia and appeared to be an ectoparasitoid on the pupa. Drosophila larvae were not observed being parasitized. A single adult parasitoid will emerge from individual host puparium. This parasitoid has been reared successfully on D. suzukii for over six generations. Adult D. suzukii emerged from 11% of pupae exposed to parasitoids compared with 85% emergence from pupae not exposed to the parasitoid. Our field and laboratory observations indicate that D. suzukii is an acceptable host for this pteromalid.