Uptake of granulovirus from the surface of apples and leaves by first instar larvae of the codling moth Cydia pomonella L. (Lepidoptera : Olethreutidae)

Cydia pomonella granulovirus (CpGV) has received considerable attention as a potential microbial insecticide for the control of the codling moth (Cydi a pomonella L.), a worldwide pest of apples. Laboratory experiments were es tablished to investigate virus uptake by first instar larvae, using a novel leaf disc bioassay technique. Virus uptake was found to be independent of active feeding mid larvae became infected simply by walking or browsing on sprayed leaf disc surfaces in as little time as 3.5 min. Infection increase d as a function of time spent on the leaf disc surface and a linear log tim e/probit mortality relationship could befitted. The bioassay technique used has potential for the realistic laboratory testing of virus spray formulat ions. A field experiment showed that virus infection could be contracted by neu ly hatched codling moth larvae both fi om the surface of sprayed leave s and sprayed fruit. The potential for exploiting this knowledge for improv ing spray formulations is discussed.