Baculoviruses are insect-specific viruses that have long been known for their insecticidal activity mainly against lepidopteran pests. They are host specific and thus, safe to non-host species. They are large, circular double-stranded DNA viruses (Family: Baculoviridae). Alphabaculoviruses are baculoviruses that exclusively infect lepidopteran larvae and produce occlusion bodies that contain rod shaped virions embedded in a polyhedral protein that, when ingested, dissolve in the larval alkaline midgut. Virions are then released and pass through the midgut cells to infect other tissues. However, how the infection is initiated in the midgut has been difficult to identify. In this talk, recent research identifying a group of viral proteins necessary for the virus to pass through the midgut to initiate infection in host larvae will be discussed. Entry into these cells is tied to a complex of proteins composed of at least nine proteins called per os infectivity factors (PIFs) found on the membrane of virus derived from occlusion bodies. Because of this new understanding of the mode of action (MOA), baculoviruses have recently been added as Group 31 to the Insecticide Resistance Action Committee (IRAC) MOA classification scheme and recognized as an important new tool to manage insect pest resistance to insecticides.
