NORWOOD – As the spring thaw settles into the wetlands of Norfolk County, local officials are preparing to take the fight against mosquitoes to the sky. The Norfolk County Mosquito Control District (NCMCD) announced this week that it will begin its annual aerial larval control applications later this month, targeting breeding grounds before the insects have a chance to take wing.
In a notice issued to local Boards of Health, District Director David A. Lawson confirmed that helicopter operations are slated to occur between April 20 and April 30. The mission focuses on large wetlands across a sprawling list of municipalities, including Norwood, Walpole, Dedham, Westwood, and Canton. In total, nearly thirty towns within the district are scheduled for treatment.
Unlike later-season efforts that residents might associate with “spraying” for adult mosquitoes, officials were quick to clarify the nature of this operation. The helicopters will be deploying a granular formulation of VectoBac GS, a biorational larvicide. Because the product is composed of heavy grains rather than a fine mist, it is designed to fall directly into the water where larvae reside, minimizing drift.
The active ingredient, Bacillus thuringiensis israelensis (Bti), is a naturally occurring bacterium that specifically targets mosquito and black fly larvae. According to environmental experts, Bti is favored for its high level of safety regarding non-target species, such as honeybees, fish, and birds.
While the District has identified a ten-day window for the work, the actual applications are expected to take only two days to complete. However, the exact timing remains at the mercy of the elements. Lawson noted that spring weather in Massachusetts is notoriously unpredictable, and high winds or heavy precipitation could lead to last-minute delays.
“We cannot pin down actual application dates with any more accuracy at this time,” the notice stated, adding that further updates will be issued as the flight window approaches. Residents in the path of the helicopters can expect to see low-flying aircraft over wetland areas during daylight hours.
The operation is conducted in accordance with state regulations, which require formal notification of aerial pesticide applications. For residents seeking more information on the schedule or the products being used, the District office can be reached at (781) 762-3681. -RD
