All natural, Biological Mosquito Control is an E.P.A. registered, biological larvicide ideal to prevent mosquitoes & fungus gnats from breeding. Quickly controls insect larvae within 24 hours, killing developing mosquitoes before they become  breeding, biting adults, including those which may transmit West Nile Virus and Equine Encephalitis, and those which may transmit Heartworm Disease to dogs and cats.