PITTSFIELD, Mass. — The city will treat one acre of Onota Lake for zebra mussels. 

On Wednesday, during a special virtual meeting, the Conservation Commission approved a series of three treatments with EarthTec QZ. During dive monitoring in August, a live adult zebra mussel was found near the boat ramp. 

Parks, Open Space, and Natural Resources Manager James McGrath said it will begin in the next 7-10 days, and that this treatment is nearly identical to that in the fall of 2024, as approved by the ConCom and other entities. 

EarthTec QZ, an EPA-registered liquid molluscicide, will be applied to a 1-acre section from a boat with GPS guidance, about 14 days apart. There will be signs and notices of treatments to alert the public. 

Karen Murray, of the Lake Onota Preservation Association, explained that the area is from the rocky point north of the boat launch to the boat launch, and a little south of the fishing pier. 

"Again, does that mean we have live zebra mussels? We don't know, but it's pretty strong evidence of a potential problem," she said. 

Over the last few years, Pittsfield has grappled with occasional findings of the invasive species.

Pittsfield and LOPA embarked on an early detection process at Onota Lake in the fall of 2023; the state Department of Conservation and Recreation had found the area near the boat launch positive for zebra mussel eDNA.