Small plot field tests were conducted to evaluate the effectiveness of an oil formulation "Florida Mosquito Larvicide", against Aedes taeniorhynchus (Wiedemann) larvae and nontarget organisms. Third instar mosquito larvae and caged brackish water species on non-target organisms were played in ponds and treated with a 37.4 liter/ha (4 gal/acre) surface treatment of the oil formulation. Excellent control of mosquito larvae was obtained and selected non-target organisms were not affected.