David Brown, who heads the Sacramento-Yolo Mosquito and Vector Control District, says the airplanes will be spraying an insecticide known as EverGreen 60-6. The doses will be so low, he says, that they pose minimal risk to humans. 

"The risk of contracting West Nile virus far exceeds your exposure to pesticides." 

But the anti-insecticide group Pesticide Watch says there are safer, non-toxic alternatives. Spokesman Paul Schramski says EverGreen 60-6 poses a threat… 

"…to our wildlife, to our waterways and pose risks to human health, particularly children and the elderly."  

The decision to spray by air follows the announcement late last week that at least two people in Sacramento County have contracted West Nile virus this year. Weather permitting, the spraying begins Monday at 7:30 PM and will continue Tuesday and Wednesday.