Summit Mosquito Dunks are designed to kill mosquitoes before they develop into adults. Containing Bacillus thuringiensis subspecies israelensis (B.t.i), a bacterium only toxic to mosquito larvae (of any species), Mosquito Dunks are harmless to people and safe to use around birds, wildlife, children and pets. Each tablet will treat 100 square feet of surface water for 30 days or more. They're even approved for use in organic production and gardening and are registered by the EPA for use in animal water troughs and fish habitats! Use Mosquito Dunks and kill those annoying mosquitoes before they're old enough to bite you.