Types of Vector Control


The purpose of the Williams County Vector Control District (WVCD) is to manage mosquito populations in and around the major population centers of Williams County, excluding Tioga as they have their own Vector Control District. WVCD conducts both aerial and truck mounted spraying operations during the summer months.

Williams County Vector Control routinely operates truck mounted sprayers which can apply ground based larvicide and adulticide treatments. Aerial treatments are conducted by contracted certified aerial applicators. Annual aerial larvicide and adulticide missions are also conducted in collaboration with the U.S. Air Force Reserve based out of Youngstown, Ohio.

Multiple factors are taken into consideration when deciding if, and when a treatment will occur. Williams County Vector Control staff routinely collect mosquito samples five days a week from traps located throughout Williams county. An increasing mosquito population coupled with favorable weather conditions inform the decision of whether or not a treatment is necessary.

The District is divided into spray blocks, which can be visualized in the map below.


Larvicides refer to pesticide products used to prevent the larval mosquito population from growing into biting adults. Williams County Vector Control uses a variety of ecologically-friendly larvicides like B.t.i (Bacillus thuringiensis israelensis).


Adulticides refer to pesticide products used to manage adult mosquito outbreaks. Williams County Vector Control uses EPA-approved products for use in ultra-low volume (ULV) applications of adulticides. Vector Control typically uses the product Zenivex (active ingredient: etofenprox), but may use the product Imperium (active ingredient: Deltamethrin) at times.

Barrier Spray

A barrier spray is a method of chemical application that is used for managing insects of medical importance. It is a longer lasting residual pesticide that is applied to man-made objects and foliage and can repel or kill insects that come into direct contact with the treated surface.

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