Chapter 4 - Basic and Applied Research: Entomopathogenic Bacteria

Abstract

Entomopathogenic bacteria and their toxins are the most commercially successful microbial insecticides. These organisms enter the host through ingestion and produce toxins and other pathogenic factors that disrupt the midgut epithelium to allow access to the nutrient-rich hemocoel, where they proliferate to cause septicemia and death of the insect host. Most commercialized microbial products are based on gram-positive bacteria in the genus Bacillus because of their long-term stability; methods are being developed to improve long-term storage of gram-negative bacterial pesticides. The most successful microbial pesticide to date is Bacillus thuringiensis, which has dominated the microbial pesticide market worldwide. The crystal and vegetative toxins from B. thuringiensi are also produced by transgenic crops, the most successful biotechnological application of bacterial entomopathogens. Other commercially available entomopathogenic bacteria include Lysinibacillus sphaericus for mosquito control, Paenibacillus popilliae to control Japanese beetle, and gram-negative bacteria in the genus Serratia to control beetle larvae. Current goals include the identification and development of novel pathogens/strains and toxins that increase efficacy and extend activity range. Challenges to further widespread commercialization and uptake of bacterial entomopathogens include the need for cost-effective products with extended stability in storage and following application and more suitable registration and legislative environments.