Bti en Westerly Starts Spraying for Mosquitos <p>Westerly residents may be awakened to the sounds of helicopters overhead Thursday morning.&nbsp; Continuing a practice begun in 1997, the town of Westerly is conducting aerial spraying against mosquitos.</p><p>The targeted areas are portions of Chapman Swamp and the swamp area adjacent to Hespar Drive.</p><p>The town uses Bti, a naturally occurring bacterium which prevents larval mosquitoes from developing into adults.&nbsp; The state Department of Environmental Management says it safe to humans and the environment.</p><p>Spraying begins Thursday at 7:00am and continues through 2:00pm.</p> Wed, 15 May 2013 18:32:53 +0000 Flo Jonic 15277 at