Yield and Activity of Gypsy Moth (Lepidoptera: Lymantriidae) Nucleopolyhedrosis Virus Recovered from Survivors of Viral Challenge

Qualitative and quantitative differences in gypsy moth, Lymantria dispar (L.), nucleopolyhedrosis virus (NPV) were monitored in surviving pupae, eclosing adults, and progeny. Regardless of mortality observed by the end of the larval period, pupal weights, adult emergence, and mating success of survivors were unaffected. However, as larval mortality increased, egg mass weight from surviving, mated females decreased. When NPV obtained from larvae in different mortality groups was tested against healthy second instars, no consistent pattern was observed. In similar tests with second instars exposed to NPV obtained from pupae and adult survivors of the larval mortality groups, NPV activity increased in proportion to incidence of original virus-induced larval mortalities. Although virus-induced mortality in progeny was low (4.7–11.5%), a high positive correlation was observed between mortality in progeny and NPV-induced mortality in the parental generation.