Adult mosquito control (adulticiding) is the only known effective measure of reducing adult mosquito populations in a timely manner. All mosquito adulticiding activities follow reasonable guidelines to avoid affecting non-target species including bees. Timing applications to when mosquitoes are most active, avoiding sensitive habitat areas, working and coordinating with property owners and personnel of other agencies when required, and following label instructions all result in environmentally sound mosquito control practices. Adult mosquito control may be conducted when all other methods of control have been exhausted or when larval control measures are unsuccessful or not possible. Most importantly, it is used for the quick knockdown of adult mosquitoes to break the disease transmission cycle.

The most common materials used by the District for adult mosquito control are pyrethrins and etofenprox. Pyrethrins are a group of naturally occurring compounds with insecticidal properties that are extracted from chrysanthemum flowers. Etofenprox is a low-toxicity pyrethroid; a synthetic version of pyrethrins.

These materials are applied in an ultra-low volume (ULV) form, similar to a fog. The tiny (micron-sized) particles impinge on flying mosquitoes. These materials affect the nervous system of insects by causing multiple action potentials in the nerve cells and delaying the closing of the ion channel. The Environmental Protection Agency (EPA) has determined that these adulticides, when used at labeled rates for mosquito control, do not pose unreasonable harm to the environment or humans. Label rates for mosquito control are normally less than one ounce per acre. These adulticides are extremely photosensitive and break down within hours in the sunlight. All products used by MSMVCD are EPA registered public health pesticides labeled for mosquito control. Applications of these products are conducted by state certified mosquito and vector control technicians in accordance with label requirements and limitations.

For more information on materials registered for mosquito control, visit the Centers for Disease Control website.