Comparative Pathogenesis of Generalist AcMNPV and Specific RanuNPV in Larvae of Rachiplusia nu (Lepidoptera: Noctuidae) Following Single and Mixed Inoculations

Abstract The South American soybean pest, Rachiplusia nu (Guenée), is naturally infected by Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and (RanuNPV). We compared their pathogenicity to fourth-instar R. larvae, evaluating time death virus spread throughout the tissues in single mixed infections. Bioassays showed that generalist AcMNPV had a faster speed of kill than specific RanuNPV, while mixed-virus treatment did not statistically differ from alone. Histopathology evidenced similar tissue tropism for both viruses, but co-inoculation resulted mostly AcMNPV-infected cells. In sequential inoculations, however, first administered predominated over second one. Implications on baculovirus interactions biocontrol potential are discussed.