Bulletins & Announcements

Larval mosquito treatment in western Placer county agricultural areas 07/22/19 through 07/23/19

We have not yet detected West Nile Virus in Placer County, and continue to do larval mosquito control treatments to reduce the number of biting adult mosquitoes later in the summer.  Please check your property for standing water and wear repellent if outdoors during dawn and dusk. 

The portions of the agricultural areas of western Placer County are scheduled for treatment for larval mosquito populations. Larval treatments involve an EPA-registered biorational* mosquito larvicide applied by a low-flying aircraft in an effort to prevent the emergence of adult mosquitoes and reduce the risk of mosquito-transmitted diseases. Treatments will occur during the daylight hours, most commonly in the early morning through the early afternoon.

Treatment area:

Western Placer County – Treatment areas are all agricultural and rural with the larvicide material applied directly to the fields (Click on map to enlarge).

Since several factors, including weather conditions, affect treatment activities, the District encourages Placer residents to check this website regularly for any changes to the treatment schedule

For an overview of our mosquito control programs, you may view the District video, available on this website.

Some important notes to consider:
Most mosquito control strategies implemented by the District are designed to prevent mosquito eggs and larvae from developing into adult mosquitoes. The District’s preferred larviciding strategies are to use biological control methods, such as mosquito-eating fish, as well as biorational* materials applied directly onto fields and pastures.

  • *A biorational larvicide is derived from a variety of biological sources, including bacteria, viruses, fungi and protozoa, as well as man-made equivalents of naturally occurring biochemicals such as pheromones and insect growth regulators. They are considered third-generation pesticides that are environmentally sound and closely resemble or are identical to chemicals produced by insects and plants.
  • The EPA considers biorational materials to have different modes of action than conventional or traditional materials, with greater selectivity and considerably lower risks to humans, wildlife and the environment.