granulovirus

Granuloviruses are a group of viruses in the family Baculoviridae, genus Betabaculovirus, characterized by the production of granular occlusion bodies that encase virions. They primarily infect caterpillar larvae (Lepidoptera) and exhibit a narrow host range, often species-specific. The occlusion bodies, called granules, typically contain a single virion, in contrast to the multi-virion occlusion bodies formed by many nucleopolyhedroviruses.

The genome is a circular double-stranded DNA molecule, usually about 80 to 180 kilobases in length and encoding dozens to a few hundred genes. Granuloviruses replicate in the nucleus of infected cells and produce occlusion-derived virions that are released when granules dissolve in the alkaline gut, enabling infection of midgut cells and subsequent systemic spread within the insect. Ingestion of occlusion bodies by larvae begins infection as the granules dissolve, releasing virions that invade midgut epithelia and establish systemic infection, ultimately producing new granuloviruses and occlusion bodies.

Industrial and agricultural use: Granuloviruses are widely exploited as targeted biological control agents for agricultural pests due to their specificity and safety for non-target organisms, including humans. Notable examples include Cydia pomonella granulovirus (CpGV) used against codling moth and Lymantria dispar granulovirus (LdGV) used in gypsy moth management. Formulations are applied like other biopesticides, often as sprays or baits, and are integrated within broader IPM programs. Resistance management and proper stewardship are important, including rotation and combination with complementary controls. In taxonomy, granuloviruses form the genus Betabaculovirus within the family Baculoviridae.