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District Detects Daytime Biting Mosquitoes In Area
mosquito district

The San Joaquin County Mosquito and Vector Control District (District) has detected the invasive mosquito Aedes aegypti in south Stockton. The District’s mosquito surveillance system discovered an adult Ae. aegypti mosquito. This species was initially found in the Brookside area of West Stockton in 2019 and in subsequent years. It was also previously detected in Escalon and a presence remains in the Escalon area as well.

“Because a resident called the District to report daytime biting mosquitoes, we can respond to this new find quickly,” said Aaron Devencenzi, Public Information Officer with the District. “Reporting daytime biting mosquitoes to the District is critical to suppressing this species which can become quite a nuisance and a potential carrier of mosquito-borne disease.”

The District is increasing surveillance efforts by placing extra traps to collect adult mosquitoes and mosquito eggs. Additionally, the District’s staff will be conducting door-to-door inspections near the Stockton residential area where the Ae. aegypti were recently detected.

The first detection of Ae. aegypti in San Joaquin County was from a sample of mosquitoes collected on Aug. 6, 2019, in the Brookside area in West Stockton. In 2021, the District found evidence of this species in Ripon and Escalon. Commonly known as the “Yellow Fever” mosquito, Ae. aegypti has the potential to transmit several viruses, including dengue, chikungunya, Zika, and yellow fever. These viruses are currently not known to be transmitted by mosquitoes in San Joaquin County or California.

Residents can continue to help in the fight against the species, said Devencenzi. If mosquitoes bite you during daylight hours, first call the District. These mosquitoes are small (about one-quarter inch), black and white, and bite aggressively during the day. Ae. aegypti lay its eggs just above the water line in small containers and vessels that hold water, such as dishes under potted plants, bird baths, ornamental fountains, tin cans, or discarded tires. Second, residents should inspect their yards and dump even the smallest amount of standing water. Be sure to clean and scrub bird baths, pet watering dishes weekly, and dump the water from overflow dishes under potted plants. Also, remove any unnecessary containers and trash around properties.

The District reminds the public to implement the following steps to avoid mosquito bites: Apply repellents containing EPA registered ingredients such as DEET, picaridin, Oil of Lemon Eucalyptus, or IR3535, Para-menthane-diol (PMD) when outdoors, according to label instructions; wear long-sleeve shirts, long pants, socks, and shoes when mosquitoes are most active; and, be sure window and door screens are in good repair to prevent mosquitoes from entering your home.

San Joaquin County residents experiencing mosquito bites during the day should report them immediately to San Joaquin County Mosquito & Vector Control District at (209) 982-4675, 1-800-300-4675 or visit

“For the public, it would be important to keep any standing water away from their house, especially that in potted plants,” Devencenzi explained. “This species lays its eggs individually on the side of containers, they can stay viable for several months to a year, and as water reaches the level that they’re at, those eggs can hatch so you can get multiple generations out of one egg laying.”

The species has been found in multiple locations throughout the state, as well as the trio of San Joaquin County communities.

“They are difficult to control … because of the way they lay their eggs, it’s very hard for us to eliminate them and they like to live around people,” added Devencenzi.

Meanwhile, the District continues to spray – primarily ground spraying – to keep down the mosquito population and the threat of West Nile virus.

Recent spray areas around Escalon included rural Northeast Escalon, Lone Tree and Steinegul area, rural north Escalon including Dove Road, Lone Tree, Steinegul and Escalon-Bellota, as well as Jacob Myers Park area, scheduled on Tuesday morning, Sept. 27.

Additional information including brochures and spray schedules, can be found at the San Joaquin County Mosquito & Vector Control District’s website,

Friday morning, Sept. 23 there were spray areas in Escalon where the Aedes aegypti species was specifically targeted, said Devencenzi.

And as far as the light rain that hit the region in mid-September, Devencenzi said that didn’t have much of an impact on the mosquito population.

“It was just a good reminder for people to clean out their gutters so they don’t collect standing water,” he said.


Times Editor Marg Jackson contributed to this report.