Submitted to: Kluwer Academic Publishers Netherlands
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2002
Publication Date: 6/30/2004
Citation: Lacey, L.A., Merritt, D.L. 2004. The safety of bacterial microbial agents used for black fly and mosquito control in aquatic environments. Kluwer Academic Publishers Netherlands. Appears in: Environmental Impacts of Microbial Insecticides: Need and Methods for Risk Assessment. Editors: H.M.T. Hokkanen and A.E. Hajek. 151-168. Interpretive Summary: Control of insect pests is traditionally accomplished using conventional chemical insecticides. Concerns about their effects on humans and the environment will limit the availability of chemical insecticides in the near future. Microbial insecticides provide alternatives to chemical insecticides and avoid environmental contamination. For the most part they do not affect beneficial insects. Our chapter discusses the usefulness of bacteria for control of insect pests and their safety to vertebrates and beneficial insects. The bacterium used most for insect control is Bacillus thuringiensis. Although it is specific for insects, some insects related to target insects may be affected. Also, repeated use of the bacterium within an environment may change the ecology of that environment. The smaller the group of insects that are affected and the more complex the environment, the less likely permanent change will result from using bacteria for insect control.
Technical Abstract: The bacterium, Bacillus thuringiensis, has been used extensively in crops, forests, and aquatic habitats for control of pest insects. Its safety and that of other insect specific bacteria for vertebrates and nontarget invertebrates have been reported in hundreds of studies. Short term effects on nontarget organisms that are unrelated to target insects is negligible. However, the effect of repeated applications on most ecosystems is relatively unknown. It is likely that any regular disruption of large insect communities, due to chemical or microbial insecticides, could have long term negative effects on ecosystem structure. The more diversified the ecosystem, the less likely that control of a single species will result in catastrophic consequences. The more species a given control method affects, the greater the likelihood of altering the ecosystem. The impact of microbial control bacteria should be evaluated in light of the risk for nontarget organisms in comparison with other interventions and the effect no treatment at all will have on an ecosystem.