Trucks will be fogging, by ultra low volume at about .75 ounces per acre, to control adult mosquitoes from about 7:20 to 11 p.m., weather permitting, district spokeswoman Deborah Bass said.
The insecticide used, Pyrocide 7067, will target a variety of mosquitoes that can transmit West Nile virus, but isn't exclusive to the virus, Bass said.
Bass said the fogging has very low risks to the public and the environment.
"The threat of West Nile virus is much greater than the product we are using," she said.
The area being fogged in Brentwood is bordered by Brentwood Boulevard on the west, Sellers Avenue on the east, Balfour Road on the south and Sand Creek Parkway on the north.
In Discovery Bay, fogging will take place inside the area bordered by Marsh Creek Road on the road, Bixler Road on the east, state Highway 4 on the south and Coral Street and Anchor Court on the west.
No future foggings are planned at this time, Bass said.