Bacterial diseases of insects

Entomopathogenic bacteria are defined by their production of pathogenic factors to cause disease in insects. Although taxonomically diverse, these bacteria commonly use the alimentary tract to enter the host and their virulence factors target disruption of the gut epithelial barrier to reach the hemocoel and cause death by septicaemia. This chapter will discuss well-characterised and some more recently studied species of Gram-positive (Bacillus thuringiensis, Lysinibacillus sphaericus, Paenibacillus popilliae, and Brevibacillus laterosporus) and Gram-negative (Serratia entomophila, Chromobacterium subtsugae, Yersinia entomophaga, Burkholdheria rinojensis, and Pseudomonas, and Rickettsiella spp.) bacterial entomopathogens. Aspects discussed include the basic ecology and biology of each species, followed by a detailed presentation of the disease process and main pathogenic factors involved. Main diseases affecting pests and beneficial insects are discussed, with special consideration given to B. thuringiensis as the most studied and best-characterised entomopathogenic bacterium.