Kills mosquitos before they are old enough to bite. Mosquito Dunks are made with Bt-israelensis (Bt-i), a highly specific biological bacterium that kills mosquito larva within hours. This product will not harm people, pets, wildlife or fish. It is very simple to use, place one dunk per month in areas where water accumulates such as ponds, rain barrels or ditches. It can be used as soon as mosquito larvae are seen in early spring, keep using all summer. Larvae are present until the end of the summer season.
One lasts 30 days and treats 100 square feet of surface water.