Viral diseases of insects

This chapter focuses on key virus families that affect wild and cultured insect species and describes current knowledge on the molecular and ecological aspects of these viruses. Insects can be infected by a variety of viruses each with distinct properties and pathologies. Depending on the taxonomic order to which the insects belong, infections with viruses of certain families are more prominent and strong co-evolutionary relationships between insects and particular virus types are often observed. Viral infections may cause diseases that are often lethal, but viruses can also remain in a persistent or latent stage and only cause a disease outbreak under certain circumstances. We illustrate the impact viruses have on particular groups of insects by providing examples of viral infections in insects in their natural environments, the application of insect viruses in biocontrol programmes, and the effect these viruses have on pollinators. Apart from viruses affecting free-living insects, we also include what is known about virus outbreaks in insects reared on an industrial scale. Furthermore, we include a brief viral disease management section for apiculture and mass rearing of other insects. We conclude this chapter with suggestions on how to obtain the necessary knowledge and tools to better control viral diseases in insects in the future.