A larvicide (alternatively larvacide)'s an insecticide that's specifically targeted against the larval life stage of an insect. Their most common use's against mosquitoes. Larvacides may be contact poisons, stomach poisons, growth regulators, or (increasingly) biological control agents. Biological agents The biological control agent Bacillus thuringiensis, also known as Bt,'s a bacterial disease specific to Lepidopteran caterpillars. Bacillus thuringiensis israelensis, also known as Bti, and Ba… (More on Larvicide)