ACTON – Quick action by a volunteer “weed watcher” for the Great East Lake Improvement Association has nipped in the bud an infestation of variable milfoil in the 1,776-acre lake along the Maine-New Hampshire line.

Fifteen months after Carol Lafond detected and removed the lone plant while snorkeling in Great East Lake, Maine environmental officials are poised to remove it from the state’s roster of 29 documented infestations of invasive aquatic plants.

The delisting of the infestation in the lake in Acton, Maine, and Wakefield, N.H., is unprecedented, according to officials. They noted that scientists regard invasive species as all but impossible to remove once they are established.

“It’s a landmark event when biologists can announce an invasive species has been eradicated,” says Paul Gregory, an environmental specialist for the Maine Department of Environmental Protection.

“Vigilance shown by Carol and her lake association to detect, remove and then continue monitoring this infestation is a blue-chip example of how invaluable volunteers are in fighting invasive species,” he said.

The early detection of milfoil in the lake ended a two-year record of no new invasive plant infestations in Maine’s inland waters, the DEP said, and no new infestations of invasive aquatic plants have been reported thus far this year.

Lafond was among 60 volunteers from the Great East Lake Weed Watchers who routinely surveyed plant populations along Great East Lake’s 18 miles of shoreline in the two states, which led biologists to believe that the milfoil she removed was newly established.

Lafond said the discovery of the plant left her with mixed feelings.

“I thought, ‘Oh no, I don’t want to be the one to tell people we have this plant!”‘ she said. But after removing the plant, she was confident she uprooted it entirely. “It wasn’t that old, so it came out easily.”

Although variable milfoil is an aggressive reproducer that can spread quickly and crowd out native plant species, subsequent monitoring by Lafond and other volunteers has revealed no sign of either regrowth of the original plant or new plants.

“Normally, volunteers like Carol are trained to identify and remove variable milfoil with a practical goal in mind: to contain the infestation effectively before it spreads elsewhere within a given lake or into another lake,” Gregory said. “Carol exceeded this goal by responding rapidly at the optimum moment when the plant was identifiable and before it had the opportunity to spread, thereby eradicating the species from this lake.”

Maine has more than 1,500 volunteers who are trained to identify invasive aquatic plants such as variable milfoil.