Santa Clara vector control crews are planning to spray insecticide next week in some Sunnyvale and Santa Clara neighborhoods, following the recent discovery of West Nile virus-positive mosquitoes.

Using truck-mounted foggers, the Santa Clara Vector Control District is set to treat the targeted areas on Monday, July 11. The treatment will begin about 10 p.m. and last for about three hours.

The areas will be in ZIP codes 94085, 94086, 94087 and 95051.

The county will spray Merus 3.0, an undiluted botanical insecticide derived from chrysanthemum flowers. The insecticide is sprayed using a very small amount of pesticide in a process known as ultra low volume treatment, county officials said.

Residents don’t need to relocate during the spraying, since the treatment poses minimal risk to people, pets, animals and the environment, according to the county.

Those who would like to take extra precautions can keep family and pets inside during the treatment, with windows and doors shut. By sunrise, the insecticide will quickly break down with the sunlight. 

Since the district applies insecticides at ultra-low volume, people aren’t likely to breathe or touch anything that has enough insecticide on it to be harmful, according to the county.

People with chemical sensitivities may want to consult their doctor for additional recommendations. 

More information is available at