VectoLex WDG, Bacillus sphaericus (Valent BioSciences Corporation), was evaluated in 3 Florida Mosquito Control Districts under operational conditions. Application rates were 0.5 and 1.0 lb/acre and an untreated control in each district. Study sites included woodland ponds, residential areas such as catch basins, and commercial business retention ponds. Pretreatment and posttreatment assessments were made with a standard dipper at designated dipping stations. The most prevalent mosquitoes included Culex quinquefasciatus, Culex nigripalpus, Culex erraticus, Ochlerotatus infirmatus, Anopheles crucians, Anopheles quadrimaculatus, and Psorophora spp. VectoLex WDG was effective for 24-35 days posttreatment with one application.