The goal of OCMVCD is to protect the public health of residents from mosquitoes and mosquito-borne diseases. The decision to use larval or adult mosquito control applications either by truck, backpack, or aircraft application will be based on surveillance information or the documentation of West Nile virus activity at a level that indicates a threat to human health.

Ground ULV Treatment Schedule

Frequently Asked Questions about ULV

Adult mosquito control will occur when there is an increase in the number of mosquitoes in a particular area, or detection of virus activity in the mosquitoes. The District conducts adult mosquito control by using ultra low volume (ULV) adulticiding equipment.  Public health pesticides (adulticides) that are registered by the US Environmental Protection Agency (US EPA) will be used to reduce adult mosquito populations and mosquito-borne disease risk.

Ground WALS Treatment Schedule

Frequently Asked Questions about WALS

WALS stands for Wide Area Larvicide Spray. WALS is an approach to larval control that uses a form of larvicide, which targets immature mosquitoes in the water using a naturally occurring bacterium to kill mosquito larvae before they emerge into biting adults. Control of mosquitoes while in the larval stage is the backbone of most mosquito control programs in California. 

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