Chapter 25 - Microbial Control of Black Flies (Diptera: Simuliidae) With Bacillus thuringiensis subsp. israelensis

Abstract

Black flies (Diptera: Simuliidae) develop in flowing water as larvae and pupae. The adult flies emerge from the water and are widely recognized as significant pests of humans and animals. Black flies also are vectors of the filarial nematode Onchocerca volvulus, the causative agent of human onchocerciasis or river blindness. As a result of their pest status, black fly populations have long been targeted by suppression programs. The most efficient and environmentally acceptable technique to suppress black fly populations is the use of larvicide applications of Bacillus thuringiensis subsp. israelensis (Bti) in rivers and streams where the pests are developing. Larvicide applications are conducted in an integrated pest management manner, and the results of larval and adult surveillance are used to target the pest population in the most efficient manner possible. Many factors (number of larvae present, stage of development, river flow rate, seston types and levels, waterway characteristics, and potential rainfall) are considered before initiating an effective larvicide application. Successful black fly suppression programs are operated around the world, many of which have involved extensive studies demonstrating the lack of effect that Bti-based larvicides have on nontarget species.