Microbial and Chemical Control

Microbial and chemical control is the use of specific microbials and chemical compounds (insect growth regulators and insecticides) that eliminate immature and adult mosquitoes. They are applied when biological and physical control methods are unable to maintain mosquito numbers below a level that is considered tolerable or when emergency control measures are needed to rapidly disrupt or end the transmission of disease to humans. Larvicides target mosquito larvae and pupae in the water. Adulticides are insecticides that reduce adult mosquito populations. All products applied by the District are registered with the California Environmental Protection Agency. Our primary goal is to protect public health and welfare by managing mosquito populations so they do not present a significant risk to our community. In the event that mosquitoes do pose a significant threat, we will respond by implementing our Mosquito and Mosquito-borne Disease Management Plan. As part of this plan, we may administer Ultra Low Volume (ULV) treatments by using backpack foggers, hand sprayers, truck-mounted foggers or aircraft, in and around areas where virus activity has been detected. Each fogging unit’s output is calibrated to ensure the correct amount of product is applied for each treatment area. To view information on the products we use, see each individual label below.

We will make every attempt to notify individuals who sign-up for the District’s notification list via e-mail of specific treatments. However, we may not be able to notify residents if immediate applications are needed to protect public health from diseases. We may also cancel a scheduled operation due to weather and/or other reasons.

Notice of Intent to Apply Public Health Pesticides for Vector Control Purposes to Surface Waters and Waters of the US


Did you know?
Most mosquitoes do not fly very far from their larval habitat, but the salt marsh mosquito migrates 75 to 100 miles over the course of its life.