What type of insecticides are being used by the Sacramento-Yolo Mosquito and Vector Control District?

. For larval mosquito control, the District typically utilizes Bacillus thuringensis (Bti) and B. sphaericus, bacterial products, or methoprene, an insect growth regulator which keeps the immature mosquito from becoming a flying adult. B. For adult mosquito control two classes of insecticides, each combined with a synergist chemical, are commonly used for adult mosquito control: Pyrethrins are the active ingredients in pyrethrum, an extract of the African flower Chrysanthemum cineriaefolium. Pyrethrins are natural insecticides that act by blocking chemical signals at nerve junctions. Piperonyl butoxide (PBO) is a synergist that is usually incorporated with pyrethrins. PBO enhances the effect of these insecticides by inhibiting cytochrome P450, a class of enzymes that break down the insecticides. This allows the insecticides to be effective with less active ingredient than would otherwise be required. The U.S. Environmental Protection Agency approves the use of insecticides nationally ...