How does Bacillus sphaericus work?
B. sphaericus spores that are eaten by mosquito larvae release toxins into the mosquito’s gut, causing the larvae to stop eating and die. B. sphaericus is only effective against actively feeding larvae, and does not affect mosquito pupae or adults. More information on the mosquito life cycle may be found on USEPA’s Larvicides for Mosquito Control Web page. Granular formulations of B. sphaericus can be applied directly to water where mosquitoes breed or may be mixed with water and other substances and sprayed from the air or ground. Depending on the formulation and environmental conditions, B. sphaericus is generally effective from 1-4 weeks after application (3). Where is Bacillus sphaericus applied? B. sphaericus is typically applied to water with high organic content where mosquito larvae live. Areas where B. sphaericus is often the preferred choice for mosquito control include waste lagoons (where animal wastes are treated) and storm water catch basins. Application of B. sphaericus
