larvicide (alternatively larvacide) is an insecticide that is specifically targeted against the larval life stage of an insect. Their most common use is against mosquitoes. Larvacides may be contact poisons, stomach poisons, growth regulators, or (increasingly) biological control agents.

Larvicides target larvae in the breeding habitat before they can mature into adult mosquitoes and disperse.  Larvicide treatment of breeding habitats help reduce the adult mosquito population in nearby areas.

Liquid larvicide products are applied directly to water using backpack sprayers and truck or aircraft-mounted sprayers. Tablet, pellet, granular, and briquet formulations of larvicides are also applied by mosquito controllers to breeding areas.

There are a number of registered active ingredients used in larvicides including:

Bacterial Insecticides, Insects that are exposed to the Bacillus species have trouble digesting food they eat after the exposure. They then die of starvation.

Insect Growth Inhibitors/Regulators (IGR's), 
prevent the larvae from maturing into adult mosquitoes.

Organophosphate Insecticides, 
affect the nervous system of insects.

Larviciding Oils
are petroleum hydrocarbons that act as surfactants to prevent larvae and pupae from breaking through the water’s surface tension and blocks their breathing tubes so that they eventually drown.