Betabaculovirus

Betabaculovirus is a genus of viruses in the family Baculoviridae, subfamily Baculovirinae. Members are granuloviruses that infect larvae of Lepidoptera (moths and butterflies) and are distinguished from the related alphabaculoviruses by their occlusion bodies, which are granular rather than polyhedral. Betabaculoviruses tend to have narrow, host-specific ranges and are widely used as biological pesticides.

Genomes and replication of betabaculoviruses are composed of circular double-stranded DNA, typically in the range of about 80 to 180 kilobase pairs, and they encode a set of core and genus-specific genes. They share essential baculoviral functions for DNA replication and late gene expression, including genes involved in forming occlusion bodies. Per os infectivity factors (PIFs) are important for initiating infection after ingestion. The virions produced inside infected cells are assembled into occlusion bodies (granules) that protect the virions in the environment and in the host gut.

Life cycle and transmission involve ingestion of occlusion bodies by a larva, dissolution of the granules in the alkaline midgut, release and infection by occlusion-derived virions, and subsequent viral replication in midgut and other tissues. This leads to production of additional occlusion bodies and, eventually, to host death. The granulated occlusion bodies distinguish betabaculoviruses from alphabaculoviruses, which form polyhedral occlusion bodies.

Applications and significance include their use as environmentally friendly, species-specific biopesticides. CpGV, the codling moth granulovirus, is one of the most well-known examples used to control codling moth in orchards. Other betabaculoviruses target pests such as diamondback moth or armyworms. Their specificity makes them valuable components of integrated pest management programs, though resistance management and regulatory considerations are important in field use.