What's in the spray? A look at business end of county's mosquito-control project (copy)

Mosquitoes are clustered at the Berkshire County Mosquito Control Project in Pittsfield. Representatives from the project told the city's Board of Health on Wednesday night that they have been unable to efficiently fight a large mosquito population this year because of a City Council vote to stop spraying this season.

PITTSFIELD — The summer’s significant rainfall brought more than just floodwaters and downed tree branches. The wet conditions triggered a hatch of years’ worth of resting mosquito eggs and resulted in a population explosion in late July and early August.

“The mosquitoes basically cover you at this point,” said Chris Horton, superintendent of the Berkshire County Mosquito Control Project. “And they’re all trying to bite you at once.” Horton estimated that, during the past month, he has received more than 3 dozen calls about what has become a “severe infestation” in parts of the city.

The American Mosquito Control Association has established a “nuisance threshold” — or the average amount of mosquitoes that would need to land on a person to be considered a nuisance.

The nuisance threshold is about 3 mosquitoes per minute. In Pittsfield, Horton said, landing counts in some parts of the city are conservatively at 40 mosquitoes per minute.

In the Everglades in Florida, before mosquito treatment began, landing counts were over 100 mosquitoes per minute.

The Mosquito Control Project and the Pittsfield Board of Health — it has overseen the project since 2012 — have a plan specifically for occurrences like these, when floods cause mosquitoes to flourish and become a potential public health risk.

As part of a 2018 compromise with the City Council, the Board of Health and Mosquito Control Project created an adult mosquito control criteria. The project agreed to stop regular “nuisance spraying” and said it would go to the Board of Health with a recommendation to conduct targeted sprays once a flood event occurred.

The decision to start sprays was at the Board of Health’s discretion, until a City Council vote this year that stopped all neighborhood spraying treatments.

In late April, councilors voted to nix the spray program, citing concern over a Boston Globe article in January that said that the Environmental Protection Agency recognized that toxic compounds — perfluoroalkyl substances, or PFAS — from faulty containers were leaching into pesticides used for control programs.

A petition from Councilor Anthony Maffuccio that served as the impetus for the vote said that “recent studies show that mosquito spraying is not supported by science, and is bad for the environment and bad for humans.”

Members of the Board of Health thoroughly rebuffed those claims during their Wednesday night meeting, and outgoing Chair Dr. Alan Kulberg said “the process has been hijacked by politics.”

Horton said that the pesticides the Mosquito Control Project uses have been approved by the Environmental Protection Agency as well as the state’s pesticide program. He said he didn’t know of any studies that supported the claims in the original petition.

Outgoing Health Department Director Gina Armstrong added that even with the safety and effectiveness of the products the project uses, the Board of Health makes sure to limit the frequency of their use.

“We’re not always going to apply these treatments or use these products, but you want it available,” Armstrong said. “When it’s the worse-case scenario, you want to have these tools available.”

While the project has been able to continue its larval treatments and catch basin programs, Horton said that those treatments aren’t the most effective at this point in the mosquito season.

Horton said that the majority of the mosquitoes his team is finding in traps this season are Culex mosquitoes — the primary transmitter of the West Nile virus. Under the 2018 mitigation plan, the Mosquito Control Project would recommend starting its adult spraying program once traps begin catching 100 Culex mosquitoes or more in a night.

Horton said that at least four traps throughout the city consistently have caught more than that number of mosquitoes this season.

On Tuesday, the project caught its first group of Culex mosquitoes with West Nile virus, in Richmond, but the group has yet to trap any disease-carrying mosquitoes in the city.

The first human West Nile virus case in Massachusetts this year was reported Tuesday, in an 80-year-old woman from Middlesex County. While some parts of the state are beginning to be classified as moderate risk for the flulike virus, the Massachusetts Department of Public Health, which is in charge of monitoring the risk of West Nile and Eastern equine encephalitis, lists Berkshire County as “remote” risk for either virus.

Horton said that might only temporarily be the case.

“It’s closing in; it’s going to be here,” he said. “This number of mosquitoes is a hazard.”

Armstrong said that the Board of Health has tried to find a provisional solution to the city’s mosquito problem, all while asking the City Council to reconsider its vote.

The issue, along with a discussion of ending the mosquito-control program altogether, was supposed to go before the council’s Subcommittee on Health and Public Safety during a meeting Aug. 12, but that meeting was canceled because of a lack of a quorum. The subcommittee likely will return to the issue at its next meeting, Sept. 9.

Meg Britton-Mehlisch can be reached at mbritton@berkshireeagle.com or 413- 496-6149.