Epidemiology of microbial control of insect pest populations

Abstract

Environmental control of a pest species involves the manipulation of one or more components of the environment so as to reduce numbers. The use of organisms of a different kind, microbial pathogens, to induce epizootics is one example of this. The major organisms concerned include viruses, sporeforming and non‐sporeforming bacteria, some protozoa and fungi. Three important parameters are considered, the host population, the pathogen population and transmission. Characteristics of the host population that limit the spread of a microbial disease include age and stage structure, innate resistance, population movements, behaviour, distribution and density and food preferences. Three important characteristics of the pathogen population are virulence and infectivity, survival and dispersal throughout the host habitat. The aim of control by induced epizootics is to approach the maximum level of infection in minimum time so as to reduce economic loss, the curve of ideal infection beings = 1 — e‐rt. Research prior...