County of San Diego West Nile Virus aerial mosquito treatment update

by Karen Pearlman | May 9, 2026 4:56 am

East County News Service

May 8, 2026 (San Diego County) — The County of San Diego will be launching its annual air war against the mosquito later this month and keep it going

Starting May 14, the County’s Vector Control Program will begin a series of aerial larvicide drops designed to thin the ranks of mosquito populations before they can take flight and spread the West Nile virus.

Unlike traditional “spraying” that targets adult insects in the air, the County will fly a helicopter over nearly 50 hard-to-reach locations — including wetlands, marshes and large areas of standing water — dropping small, granular grains of larvicide directly into the water.

These grains are designed to act like birth control for mosquitoes and contain a special larvicide that prevents young larvae from maturing into biting adults.

County officials say that the treatment is environmentally friendly and safe for people, pets, plants, and other wildlife like birds and fish.

The May 14 launch is the first of several planned. County officials say that aerial drops will recur every three to four weeks through the end of October, which typically marks the end of the peak mosquito season in San Diego County.

Health leaders say that the West Nile virus[1] remains a persistent threat in the county. While many who contract the virus show no symptoms, it can lead to severe neurological issues or even death in vulnerable populations.

The County notes that the community’s role in fighting the mosquitoes is vital. Residents are urged to turn over any containers that hold standing water, including saucers under flower pots, birdbaths, and clogged rain gutters, and drain them.

Visit the County Vector Control website[2] to see a list of neighborhoods on the flight path, which include Escondido, Kumeyaay Lake in Mission Trails Regional Park, Lakeside and Santee.

Follow @SDFightTheBite[3] on Facebook and X (formerly Twitter) here[4], and for more information, visit SDFightTheBite.com[5]

Source URL: https://eastcountymagazine.org/county-of-san-diego-west-nile-virus-aerial-mosquito-treatment-update/

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