Westerly To Apply Mosquito Larvicide Across Chapman Swamp

WESTERLY, RI — The Town of Westerly plans to begin aerial application of mosquito larvicide across 500 acres of Chapman Swamp and nearby swamplands by helicopter on Tuesday.

Weather permitting, the application will take place May 4 between 8 a.m. and 2 p.m. If it rains, it will take place on the next calendar day that weather permits, the Rhode Island Department of Environmental Management announced.

The substance known as Bti will be used. RIDEM says Bti is a naturally occurring bacterium applied in granular form. They say it is an environmentally friendly product that does not pose a risk to human health. In a news release, RIDEM said Bti is used to control mosquito breeding in swamps and other habitats.

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“Larviciding is recommended as part of the state's action plan for West Nile Virus and Eastern Equine Encephalitis (EEE) and considered an effective strategy to reduce mosquito populations and related disease risk,” RIDEM stated.

In most communities, the state recommends applying larvicide by hand to roadside catch basins. In the Chapman Swamp area, aerial application is done 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. The targeted areas include portions of Chapman Swamp and swampland adjacent to Hespar Drive.

The Rhode Island Department of Health offers mosquito tips at http://www.health.ri.gov/mosquito.