The effects of timing and dose of entomopoxvirus infection in Pseudaletia separata (Lepidoptera : Noctuidae) larvae on the development of Cotesia kariyai (Hymenoptera : Braconidae)

The effects of the timing and dose of entomopoxvirus infection in Pseudalet ia separata larvae on the development of a braconid larval parasitoid, Cote sia kariyai, were studied under laboratory conditions. The infection of lar vae with an entomopoxvirus (PsEPV) was deleterious to the development and s ubsequent survival of C. kariyai. The survival and development of C. kariya i in PsEPV-infected P. separata larvae depended on the viral dose, timing o f viral infection and the length of time between parasitization and viral i nfection. The percentage of hosts with emergence of C. kariyai decreased wi th increases in PsEPV concentration and increased with progressive inoculat ion stages of larvae. No parasitoid larvae emerged from PsEPV-infected host s when host larvae were exposed simultaneously to parasitization and inocul ation of lethal dose of PsEPV. Survival of C. kariyai in PsEPV-infected hos ts increased as the time between parasitization and subsequent viral exposu re was increased. The body length of parasitoid larvae developing in PsEPV- infected hosts decreased as the inoculation dose of PsEPV was increased. Pa rasitized larvae were more susceptible to PsEPV than nonparasitized larvae, regardless of the timing of parasitization and viral inoculation.