Impact of the release of entomopathogens in the environment

Abstract

The environmental impact of entomopathogens depends on two factors: the fate of the pathogen after its release, and the effects of the pathogen on various components of the environment. Three factors affect the fate of a released entomopathogen: its persistence, population growth, and dispersal. Environmental fate after release varies with the pathogen species and environmental factors. Data concerning environmental effects after release are scanty but somewhat similar for viruses, bacteria and fungi. The major demonstrated effects are the increase in numbers of pathogen units in the environment and decrease in host-insect numbers and damage to crop plants. Viruses and bacteria have been demonstrated to harm invertebrate parasitoid and predator populations, primarily by reducing their common resource, the host insect population. However, they rarely have as severe an effect as chemical insecticides. The potential environmental impact of recombinant-DNA entomopathogens has become a primary consideration in their release for microbial control. There are three major concerns about releasing such organisms: they might have unexpected, deleterious properties after release; they could cause ecological disruptions as have other biological introductions; and they could transfer genetic material to other organisms, causing the first two areas of concern to resurface. Overall, R-DNA organisms are perceived as having a low probability of causing environmental harm but potentially severe consequences if harm occurs.