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Westerly Postponing Mosquito Larvicide Spraying Until Thursday, May 12, Due To High Winds

PROVIDENCE The Rhode Island Department of Environmental Management (DEM) today announced the Town of Westerly has postponed the aerial application of mosquito larvicide across 500 acres of Chapman Swamp and nearby swamplands by helicopter from today to tomorrow, Thursday, May 12, due to high winds. Spraying will take place between 8 AM and 2 PM.

Bti, a naturally-occurring bacterium applied in granular form to control mosquito breeding in swamps and other breeding habitats, will be applied. Bti is used to kill developing mosquito larvae by being applied to standing water where those larvae are found. It is an environmentally-friendly product whose toxins specifically affect the larvae of only mosquitoes, black flies, and fungus gnats and does not pose a risk to human health. Larviciding is recommended as part of the state's action plan to control West Nile Virus and Eastern Equine Encephalitis (EEE) and considered an effective strategy to reduce mosquito populations and related disease risk.

In most communities, the state recommends applying larvicide by hand to roadside catch basins. In the Chapman Swamp area of Westerly, aerial application is recommended given the area's remote location and large footprint. Mosquitoes carrying the EEE virus were found in Chapman Swamp in 1996, 2003, 2019 and 2020. Since 1997, the Town has applied Bti annually to help control mosquito breeding. Additional dates for spraying may be scheduled by the Town; the targeted areas include portions of Chapman Swamp and swampland near Hespar Drive.

For mosquito prevention tips, visit the Rhode Island Department of Health's website.

For more information on DEM programs and services, visit Follow DEM on Facebook, Twitter (@RhodeIslandDEM), or Instagram (@RhodeIsland.DEM).

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  • Department or agency: Department of Environmental Management
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  • Release date: 05-11-2022

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