Hz-2V is a rod shaped, enveloped, non-occluded insect virus which has a large circular, double stranded DNA genome. Productive replication of Hz-2V in insect reproductive tissues results in the malformation of these tissues and sterility of the adult moth. Analysis of the Hz-2V genome revealed the presence of a carboxylesterase gene (ORF-7) which has a 120 amino acid region homologous to the functional domain of the drosophila juvenile hormone esterase (JHE). Upon examination of the level of JHE in female reproductive tissues during insect development, it was found that although JHE titers in tissues from healthy and infected insects followed the a pattern of decreasing as the insect matured, the JHE titers in reproductive tissues from virus infected last instar, females where significantly lower than that in tissues from healthy females. This is surprising since general esterase levels in the reproductive tissues from infected last instars is higher than in tissues form healthy last instars. The pattern of ORF-7 gene expression was examined in different life stages of the host and compared with that of two virus structural protein genes. These results showed that while the virus structural protein genes were expressed in second instars through late pupae, ORF 7 gene expression was first detected in third instars indicating a stage specific expression of this gene possibly by host transcription factors involved in the developmental regulation of the insect.