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TextProactive Catch Basins Treatments
Stormwater catch basins are treated with a larvicide in three cycles during the West Nile virus season in order to reduce the larval mosquito population of known vector species. Fairfax County uses a biological larvicide, Bacillus sphaericus, which specifically kills mosquito larvae. The DCIP also encourages County residents to eliminate mosquito larval habitats around their homes, in their communities and neighborhoods.
First Treatment Cycle
The first treatment cycle begins in May and includes CBs in a large portion of the county,
as seen here (Jpg image, 60K). This area contains over 65,000 CBs.
Many of the CBs in this area are newer and are in good condition (not
containing water). These areas of the County are not subsequently treated
during the year.
Subsequent Treatment Cycle
After the initial large treatment cycle, a smaller portion of the
County, as seen here (Jpg image, 59K), is treated with a larvicide on
a regular basis (monthly). This portion of the County contains
approximately 33,000 CBs that are older and often have structural
problems leading to water retention.08/09
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