Codling moth, Cydia pomonella (L.), larval bioassays were carried out on apples and leaves collected from trees treated with the commercially available codling moth granu- lovirus, Virosoft CP4®, to estimate the persistence of the product over time. The virus had a significant effect on survival of laboratory derived codling moth larvae placed on apples collected up to five and eight days post-treatment. Larvae died with virus symp- toms after feeding on treated foliage and the leaf bioassay was easier to count than the apple bioassay. A combination assay, exposing larvae to leaf discs and fruit may more accurately account for potential exposure of wild neonate codling moth to virus in treated orchards. The addition of fish, soybean or mineral oils to Virosoft CP4® treat- ments did not significantly increase the efficacy or persistence of the viral insecticide on apples in this study.