Napa County Mosquito Abatement District (NCMAD) has been controlling mosquito populations for the citizens of Napa County since 1925. The Board of Trustees comprised of representatives from each incorporated City and the County-at-large governs the District. There are currently eight employees who are responsible for controlling mosquitoes throughout the County.

NCMAD works closely with other public agencies, park districts and wineries to provide an effective and environmentally sound mosquito control program. The District also works with planning agencies to minimize mosquito production in wetland restoration and enhancement projects.

There are 20 known species of mosquitoes in Napa County. Read more about them here.

Mosquito Control

Your District controls mosquitoes by targeting the larvae, which are found in stagnant water. By preventing adult emergence, a control program can be conducted that has the least impact on the environment. Six methods are used to control mosquitoes, read more about them here.


There has been a lot of public concern and confusion about mosquitoes and AIDS. Scientific studies conducted by the Centers for Disease Control and the World Health Organization have shown that mosquitoes DO NOT transmit AIDS.  For more information, here is an article from Nature.com about why mosquitoes cannot transmit AIDS.

In California, mosquitoes are monitored and controlled primarily for public health reasons, such as West Nile Virus, malaria, encephalitis, dog heartworm and sensitivity to bites. Some mosquitoes are also controlled because of their annoying habits.

With the exception of recent West Nile Virus cases, human mosquito-borne diseases have declined significantly in California since the creation of mosquito and vector control agencies. Residents should be aware that West Nile Virus, dog heartworm and encephalitis viruses are still present in Napa County.

Go here for more information on Mosquito-Borne Diseases.