In the case of an increase in the number of mosquitoes in a particular area, or detection of an arthropod-borne virus in mosquitoes, wild birds, or humans, the District may decide to conduct ground or aerial ultra low volume (ULV) adulticiding activities.

Ground ULV is carried out usually in urban areas with special equipment mounted on the truck to control adult mosquitoes.

Aerial ULV is usually carried out in rural areas by helicopter or small airplane.

The adulticides are applied at very low dosages. The low dosages, plus natural degradation by UV light and water, ensure minimal risk. The District uses pyrethroid-based products for ground and aerial ULV adulticiding. Pyrethroids are a synthetic insecticide, modeled after a botanical insecticide produced primarily from the flowers of Tanacetum cinerariaefolium, which is a species of chrysanthemum plant family, which acts as the plant’s own insecticide to keep insects away.

At the time of adulticiding the District will post the information on its website as well and by using neighborhood signs posted near the treatment.

For questions, please contact the District at 760-342-8287 or by email. To be notified via email of any adulticiding activities, please sign up for notifications by clicking the "Join our mailing list" button on this page.

If you would like to request that ground adult control applications are not made to your property, please complete the No Treatment Request Form and the District will try to accommodate the request without jeopardizing public health.  Please note that we cannot take non-treatment requests into consideration for aerial treatments.