Infection of larvae of the smaller tea tortrix, Adoxophyes sp., by an entomopoxvirus (AsEPV) adversely affected the development and survival of the endoparasitoid, Ascogaster reticulatus. Percentages of emergence of parasitoid larvae that developed in AsEPV-infected hosts were significantly lower than those of parasitoid larvae that developed in noninfected hosts. The percentages of emergence of A. reticulatus were significantly greater for parasitoids developing in the host larvae that were exposed to AsEPV in third and fourth instars than for the parasitoids developing in the host larvae that were exposed to AsEPV in first and second instars. Successful pupation and eclosion of parasitoids significantly increased as duration between parasitization and administration of AsEPV increased. No parasitoid larvae developing from hosts that were inoculated with AsEPV in the first or second instars pupated and emerged as adults, whereas 13.8 and 54.0% of parasitoids developing from the hosts that were exposed to AsEPV in the third and fourth instars, respectively, pupated. The development of parasitoids in AsEPV-infected hosts was delayed. This developmental retardation was more severe in parasitoid larvae developing in the early-infected hosts than in those developing in the late-infected hosts. The average times required for death due to AsEPV infection were significantly shorter in parasitized hosts than in non-parasitized hosts. Significant numbers of parasitized and infected larvae exhibited apolysis in preparation for the final larval molting. This abnormal metamorphosis appeared to be a possible reason for the earlier death of the parasitized and infected hosts.