Kills Mosquitoes before They re Old Enough to Bite!®. Non-toxic to all other wildlife , pets, fish, and humans. Simply apply Mosquito Dunks® to any standing water, or water garden. Kills within hours lasts for 30 days or more. Labeled For Organic Gardening by the USEPA. Highly effective low impact product The Mosquito Dunks® are 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. Package contains 2 Dunks.