Westborough, Grafton Mosquito Pesticide Spraying Starts Up

WESTBOROUGH, MA — The Central Massachusetts Mosquito Control Project will begin pesticide spraying in residential areas to control the disease-carrying bloodsuckers starting on Wednesday.

The mosquito control project will spray in a combined area including Westborough, Grafton and Southborough on June 2, 8, 9, 15, 16, 23, 29 and 30. The CMMCP releases a list of likely spraying locations during spraying days around 3:30 p.m. Check the locations here.

Officials say the pesticides used to control mosquitoes pose a low risk of harming humans and pets. But the mosquito control project still advises people to remain indoors, close windows and doors turn off window air conditioners and fans. Residents should allow between 15 and 20 minutes to pass after the spraying truck leaves before going back outside.

The CMMCP uses a product called Zenivex E4 to kill adult mosquitoes. Residents can also opt out of spraying if desired. Separately, the CMMCP applies biological pesticides across wetland areas in spring to kill mosquito larvae. Those products use a bacterium that destroys the mosquito larvae.

Adult mosquitoes carry diseases like Eastern Equine Encephalitis and West Nile virus. EEE cases spiked in 2019; two human cases were detected in 2020 and none in 2021 — although the state did find mosquitoes positive for the virus in those years. West Nile has been the bigger threat over the last two summers, with nine cases over the warmer months of 2021.