Sherborn Board of Health Unanimously Rejects West Nile Mosquito Spraying Proposal

SHERBORN — September 3, 2025 — Sherborn's Board of Health voted 4-0 to reject a mosquito adulticide spraying proposal near Farm Pond. Meeting Wednesday evening, the four-member board — Co-Chair Julie Dreyfuss, Steve Constantine, Diana Hook, and Rebecca Honeywell — declined a request from the Central Massachusetts Mosquito Control Project to spray Zenvex, a synthetic pyrethroid, along Farm Road and Forest Street following a West Nile virus detection in a local catch basin. Health Administrator Sarah Lapin presented the proposal, noting the chemical dissipates within six to 12 hours and is applied via truck-mounted ultra-low-volume sprayers with a range of roughly eight to 10 meters from the road. Public commenters including aquatic scientist Marianne Moore warned that pyrethroids are "very toxic to all sorts of aquatic animals" and raised concern about runoff into Farm Pond, while resident Nick argued the state "simply don't know" how effective roadside spraying is. Health Agent Mark Oram recommended a formal vote; the board also directed staff to notify the mosquito project of its decision and said it would reconsider if Eastern equine encephalitis cases emerge before the first hard frost. The board separately maintained a cyanobacteria advisory at Farm Pond, with retesting results expected September 5 to determine whether an annual perimeter swim on September 6 can proceed; bacteria levels measured August 28 stood at 2,400 cells per milliliter, well below the state's 70,000-cell threshold.