PITTSFIELD, Mass. — Pontoosuc Lake will be treated for weeds with a contact herbicide on Thursday, June 17. 

Last week, the Conservation Commission OK'd a request for Diquat treatment on 53 acres of the lake.

"We have four non-native and invasive species, three of which we are controlling with the use of herbicides, and if we didn't do that control, the weeds would take over the lake and the shore," explained Lee Hauge, president of the Friends of Pontoosuc Lake and Lanesborough's harbormaster. 

"All the shorelines would be unusable for swimming and even fishing, and you'd only have the center half of the lake, where you could do any boating or swimming if you could get out there." 

Pittsfield and Lanesborough equally share the management of the lake and associated costs.

Hauge explained that underwater weeds were harvested for almost 20 years, and it was successful in making the lake accessible for swimming and boating, though over the years, he said, the process favored the propagation of Eurasian milfoil, which spreads by fragmentation. 

"And so the result of that 20 years of harvesting control was the lake being choked by Eurasian milfoil, and the native desirable weeds were choked out of being able to grow because of the proliferation of the milfoil," he said. 

The application is for 53 acres, and Pontoosuc will need to be treated again in August. This will require permission from the ConCom.