Vector control officials will conduct anti-mosquito spraying Friday in a Riverside neighborhood adjacent to an open space preserve to eradicate growing infestations that pose a potential risk to public health.
The Northwest Mosquito & Vector Control District has scheduled “ultra low-volume” insecticide treatments between 3 a.m. and 6 a.m. Friday in the residential area accessible via Canyon Crest Drive and Ransom Road.
That’s due west of Sycamore Canyon Wilderness Park.
“This is being conducted in response to elevated adult mosquito abundance in this area,” according to the district.
The area targeted for spraying, depicted via an agency map, encompasses the subdivision between Ransom to the north and Via Vista Drive to the south, east to Canyon Crest Drive and west to about Windemere Way.
Anti-mosquito spraying involves the use of chemicals approved by the U.S. Environmental Protection Agency. Pesticides are emitted as a mist dispersed from machines anchored in the backs of pickup trucks. Officials recommended that during operations, residents stay indoors and keep windows closed until at least 15 minutes after the trucks have departed.
One human West Nile Virus infection has been documented in the county so far this year. Statewide, 65 infections have been recorded to date in 2026, according to the California Department of Public Health. Five of those, in Central and Northern California, resulted in fatal outcomes.
In 2025, one human WNV infection was documented in Riverside County, and the patient recovered.
Mosquitoes typically become carriers of the virus after feeding on an infected bird and can then spread the potentially lethal strain to animals and humans. Those at greatest risk include seniors and individuals with compromised immune systems.
Symptoms may never materialize, but can include fever, headache, nausea, body aches, skin rashes and swollen lymph nodes.
Mosquito season in Southern California generally spans May to October. To reduce exposure to mosquitoes, residents are urged to:
— spend as little time as possible outdoors at dawn or dusk, when mosquitoes are generally on the move;
— wear long pants and long-sleeved shirts during outdoor activity in mosquito-prone areas;
— use insect repellent;
— ensure door and window screens are fitted properly to keep bugs out; and
— get rid of standing water, aside from pools properly treated with chemicals.
Further information is available at northwestmvcd.org/, or by calling 951-340-9792.