ProcellaCOR herbicide use expanded to more Adirondack waters in 2024

Pitched Lake George fight ends with lake’s first-ever chemical control of invasive milfoil

By Zachary Matson

When an appeals court in May sided with the Adirondack Park Agency’s approval of a plan to use an herbicide in Lake George, it set the stage for a pitched fight over the first-ever chemical control of invasive plants in the Queen of American Lakes.

Despite a concerted effort by the Lake George Association to block the use of ProcellaCOR in a pair of north basin bays to kill invasive Eurasian watermilfoil, state agencies and courts rejected a litany of concerns from residents and the lake association. 

Property owners argued that the herbicide, which has been used in scores of lakes across the state and Northeast, had not been tested enough to ensure safety to their drinking water or Lake George’s prized environment. 

The Lake George Park Commission, which sponsored the herbicide project, argued that it had been vetted by state and federal experts and approved for use in countries around the world. Previous methods of milfoil control were costly and largely ineffective, and ProcellaCOR record of use was compelling, proponents said. 

APA’s approval of the herbicide, despite widespread public opposition, contrasted with how a similar fight played out in Vermont.

Ultimately, the herbicide was dropped into Lake George on June 30, marking the first chemical management of an invasive plant in the lake’s history. 

The herbicide was not detectable within 24 hours, according to monitoring, and when divers visited the site a month later they observed dead and dying milfoil throughout the application sites. 

Tensions between the LGA and park commission ran high, but in the wake of the monitoring the leaders of the two organizations went public with a truce and promise to work together to study the herbicide’s impact and whether to expand its use to other infested bays.

The lake association’s new leader said he planned to follow the science as the organization formed a view of future herbicide uses on the lake. 

Lake George wasn’t the only lake to deploy ProcellaCOR as lake communities continued to line up for approval to use the latest weapon in the fight against the Adirondacks’ most pervasive aquatic invader.

Paradox Lake, Chateaugay Lake, Brant Lake and Caroga Lake all used the herbicide over the summer. Residents on Horseshoe Pond in the northern Adirondacks rallied to raise money to treat their private pond, while also pressing state officials to do the same on the adjacent Deer River Flow, where invasive milfoil still flourishes.