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Mosquitoes Can Thrive Despite Drought Conditions

Cotati, CA. June 8, 2021- As residents of Marin and Sonoma counties brace themselves for another drought year, officials from the Marin/Sonoma Mosquito and Vector Control District urge residents not to let their guard down when it comes to mosquitoes.

“Mosquito production during drought years does not necessarily decrease,” stated Dr. Kelly Liebman, Scientific Programs Manager for the Marin/Sonoma Mosquito and Vector Control District. “Sources of ponded water still exist during a drought. The organic content in the water tends to increase the longer the water persists. This is an ideal environment for mosquitoes to grow.”

Drought conditions may also play a role in an increase of West Nile virus activity as birds and mosquitoes congregate in areas still holding water. Mosquitoes become infected with West Nile virus when they feed on infected birds.

Residents are encouraged to maintain, manage or eliminate all types of standing water on a regular basis. Keep in mind that mosquitoes need as little as a 1/2 inch of water to complete their life cycle, so water sources utilized by mosquitoes may not be obvious.

Use this checklist to help minimize mosquito production around your home:

  • Store containers upside down, covered, or in a sheltered area.
  • Cover rain barrels or other water storage containers tightly with a fine mesh screen (1/16 inch).
  • Place mosquitofish into contained water sources such as ponds, water troughs, neglected pools and ornamental water gardens.
  • Keep rain gutters clear of leaves and other debris.
  • Screen septic tank vent pipes with a fine mesh screen (1/16 inch). Check tank lids for cracks and repair if needed.
  • Don't overwater lawns or potted plants. Flush out plant saucers with a hose or drill holes in the bottom to allow for better drainage.
  • Report mosquito issues to the District at 707-285-2200 or online at

The Marin/Sonoma Mosquito and Vector Control District's programs and services are funded through property taxes and benefit assessments and are provided at no additional cost to all residents of Marin and Sonoma counties.

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