Adult Mosquito Control Pesticides

Zenivex E4

What is Zenivex┬« adulticide and how is it used? 


Zenivex┬« contains a pesticide called Etofenprox, a member of the category of pesticides called non-ester pyrethroids, which are synthetic versions of pesticides produced by chrysanthemum flowers called pyrethrins. Zenivex┬« does not require a synergist such as piperonyl butoxide. The U.S. Environmental Protection Agency (EPA) has classified Etofenprox as a reduced risk pesticide. It poses a low risk to human health and the environment when used properly as part of an integrated mosquito control program. As formulated in Zenivex┬« adulticide, Etofenprox is considered a non-carcinogen, non-teratogen and non-mutagen. 


Zenivex presents a minimal risk to humans, pets and non-target species. Etofenprox presents a low toxicity to birds and dried foliar residues are not harmful to honeybees. Applications occur after sunset when honeybees aren’t active. Zenivex E4 is toxic to fish, but buffer zones are in place to avoid spraying around fish habitat.


This pesticide kills mosquitoes effectively, yet biodegrades rapidly in the presence of sunlight and/or microorganisms.


Etofenprox is readily found in flea and tick prevention treatments for dogs and puppies, and at much higher concentrations than what is used for mosquito control.



East Middlesex is applying Zenivex E4 at a rate of around 1 oz. per acre, which is equivalent to about two tablespoons per acre. The active ingredient, etofenprox, makes up 4% of that amount, therefore, less than 1/10th of a tablespoon of the active ingredient is being applied per acre.

An Ultra Low Volume sprayer located in the back of a pick-up truck is used for the mosquito control effort. The average droplet size of the spray falls between 10-30 microns. A micron is 1/25,000 of an inch. For perspective, human hair is 100 microns. 

Mosquitoes are the target. Being that mosquitoes are so small, only a small amount of Zenivex E4 is needed to reduce mosquito populations. The small amount needed to reduce mosquito populations is not expected to have negative impacts on non-target animals or the environment. 



EPA Information on Mosquito Control


Label and Material Safety Data Sheets (MSDS)

-Zenivex E4