Kill mosquito larvae quick, within 24 hours-before they are old enough to bite! Environmentally sound biological mosquito control, EPA registered in all 50 states. Safe enough to use even in bird baths. Simply sprinkle in any standing water, including water gardens for a quick kill. 1 teaspoon treats 25 square feet of surface water. Use Mosquito Dunks for residual protection for 30 days or more! 36 oz. container.