Mosquito Dunks kill mosquitos before they?re old enough to bite! They are North America's best-selling home owner mosquito control product. The only product with BTI, a bacteria toxic only to mosquito larvae that lasts 30 days and treats 100 square feet of surface water. Mosquito Dunks are deemed fit for Organic Production by the USEPA in accordance with the USDA's National Organic Program (NOP). Mosquito Dunks are non-toxic to all other wildlife, pets, fish, and humans. Simply add Mosquito dunks to any standing water or water garden - kills within hours! Registered for sale by Health Canada Pest Management Regulatory Agency.