Northern California cities to obtain West Nile aerial spray

One Piper Aztec twin-engine aircraft sits on the flight line Sunday, Aug. 6, 2023, at McClellan Airport, that will be used for aerial spraying because of high mosquito infection rates in Davis and Woodland.

One Piper Aztec twin-engine plane sits on the flight line Sunday, Aug. 6, 2023, at McClellan Airport, that will probably be used for aerial spraying due to excessive mosquito an infection charges in Davis and Woodland.

Aerial treatments to mitigate the spread of West Nile virus will be applied to areas of Yolo County beginning Sunday night, authorities said.

The announcement came Friday after the Sacramento-Yolo Mosquito and Vector Control District received lab results that indicated high mosquito infection rates in Davis and Woodland, according to district spokeswoman Luz Maria Robles.

Two Piper Aztec twin-engine aircraft sitting at Sacramento McClellan Airport will be used. Spray treatments in both cities are scheduled between 8:30 p.m. and 11 p.m. Sunday and Monday.

Steve Ramos, assistant manager for the Sacramento and Yolo district, ambled around one of the planes on the runway Sunday morning while the sun beat down on what would be one of Sacramento’s hotter days. He said the spray treatments are not harmful to humans.

The substance used is Naled, an insecticide used in the U.S. since 1959, according to the district website.

“It’s less than an ounce over an acre,” Ramos said. “We recommend people do what makes them comfortable.”

Robles said that 157 mosquito samples have been collected in Yolo County in 2023, a sharp increase from the previous number, 47, reported on July 20. Seven dead birds have also been reported in the county, Robles said.

Heat worsens West Nile activity by speeding up the hatching of mosquitoes, officials say. The California Department of Public Health also said in June that record rain totals this past winter have led to increases in mosquito populations.

“We do have ongoing agricultural applications that treat the surrounding rice fields that’s done routinely throughout the mosquito season,” Robles said. “However, these urban aerial applications are targeting mosquitoes that are infected with West Nile virus, and the objective is to interrupt the transmission cycle and protect the residents.”

Statewide, there have been eight human cases reported in 2023. Severe cases in humans are rare, officials say.

District officials said mosquito prevention is best achieved when residents drain standing water, avoid being out at dawn and dusk, wear long sleeves and pants and insect repellent, and close doors and window screens.

Cases can be reported at 800-429-1022 or online at

This story was initially printed August 6, 2023, 2:11 PM.

Associated tales from Sacramento Bee

Alex Muegge is a reporting intern for The Sacramento Bee. He graduated from Sacramento State with a bachelor’s diploma in political science and journalism.

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