No pesticide is considered completely safe, and the EPA urges the public and agencies to follow directions for application and use carefully. Larvicides Mosquitoes have four stages in their life cycle. They begin as eggs that hatch into larvae when immersed in water. The larvae thrive in the water and may swim to the surface to breathe. From larvae, the mosquitoes grow into pupae and then adults.
Larvicides kill mosquitoes when they are larvae.
Microbial Larvicides Microbial larvicides are made of bacteria that destroy the larvae. The larvicides are placed in pools of water where mosquitoes are thought to breed such as marshes. Bacillus thuringiensis israelensis occurs naturally in soil and has been used as an insecticide since 1983. The larvae eat the bacteria, which then destroy the guts of the insects. Bacillus sphaericus works similarly.