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Mosquito Dunks

Kills Mosquitoes before they're old enough to bite!



Mosquito Dunks are a form of Bacillus thuringiensis v. israelensis in a solid form. As they float in the water where you put them they slowly release the Bt on the water surface. The Bt then gradually settles to the bottom where the mosquito larva eat it and die. Mosquito Dunks are 2 inches in diameter and 1/2 inch thick, with a small hole in the center. The Dunks float on top of the water and will be effective for approximately 30 days. While floating, they slowly release the larvicide that settles in the water where it is eaten by mosquito larvae. Alternate wetting and drying will not reduce their effectiveness. The center hole can be used to anchor the dunks in place with a string or stake. Recommended application rates are 1/4 dunk for 1-5 square feet of water surface area and one dunk for 25-100 square feet of water surface area regardless of the water depth.


Mosquito dunks can even be used in areas that run wet and dry, such as areas prone to periodic flooding and they still remain effective!

  • 1 Dunk treats 100 square feet
  • Dunks can be staked or anchored in place to keep them from washing away
  • Bti does not harm people, pets, birds, fish, or plants. Click here to read the EPA fact sheet and toxicity report for Bti

Mosquito Dunks can be used in many places where we find mosquito larva. Even a tree crotch that catches and holds water can be a breeding ground for mosquitoes! You don't need to use the whole dunk for small places either- you can break off a small piece as needed.


Places where dunks can be used:


  • Bird Baths
  • flower pots
  • tree holes
  • old tires
  • rain barrels
  • roof gutters
  • areas that have standing water etc.

Mosquito Dunks release a constant, low dose of Bti so early instars may survive temporarily. However, continuous ingestion of the active ingredient produces a chronic infection, which kills the larvae so you will not observe pupae and the adult mosquitoes will not emerge. Made with natural Bti, Mosquito Dunks represent a major breakthrough for people and the environment when compared with the traditional toxic chemical approach to mosquito control.


Bti is a bacterium that controls mosquitoes and black flies in their larval filter feeding stage of development. The larvae die after consuming the bacteria that causes a disease specific to them but is harmless to all other forms of wildlife.





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