Ascoviruses

Ascoviruses are a genus of invertebrate iridescent viruses (IIVs) belonging to the family Ascoviridae. These viruses infect a wide range of insects, particularly lepidopteran species, which are often agricultural pests. Ascoviruses are characterized by their large, enveloped virions that possess an iridescent blue-green appearance when viewed under a light microscope in high concentrations. This iridescence is due to the crystalline array of viral particles within infected insect tissues.

The genome of ascoviruses consists of double-stranded DNA, typically circular. The replication cycle of ascoviruses is complex and involves both nuclear and cytoplasmic phases within the host cell. Infection usually leads to the development of chronic, non-lethal symptoms in the larval stage, but can cause increased susceptibility to other stressors or pathogens. However, when the infected insect enters the pupal or adult stage, the virus replicates extensively, leading to the formation of occlusion bodies. These occlusion bodies, which contain the infectious virions, are released upon the death and decomposition of the host, facilitating transmission to new hosts through ingestion.

Ascoviruses are of interest in biological control programs due to their potential to weaken or kill insect pests without harming non-target organisms. Their specificity and natural occurrence make them attractive candidates for integrated pest management strategies. Research continues to explore their molecular biology and potential applications in agriculture.