Group decides to use herbicide to fight Lake Dunmore milfoil

SALISBURY — After more than two decades of using machinery and manpower to remove Eurasian milfoil from parts of Lake Dunmore and Fern Lake, an association of local property owners wants to employ a new ally to eradicate the nuisance weed:
The Lake Dunmore Fern Lake Association (LDFLA) has applied for permission from the Vermont Department of Environmental Conservation to apply an herbicide known as Renovate (Triclopyr) to the most milfoil-infested areas of the lakes. In Dunmore, that would mean applying Renovate to a combined total of around 100 acres in various milfoil pockets at the southern and northern ends, as well as an area in the eastern side of the center of the lake known as “the spine.”
“For years, we have tried to avoid going to this step,” LDFLA President-elect Jim Foley said of herbicide application. “But we have gotten to a point where we are looking at the numbers, and it has just overwhelmed our crews.”
Those crews — a mixture of paid staff and volunteers — have put in untold hours battling milfoil since it was first discovered in Lake Dunmore in 1988. The association quickly initiated some volunteer control efforts, but transitioned to a more comprehensive, paid management program after a second infestation was discovered at the north end of the 985-acre lake in 1994.
A staff of around 12 have been operating suction harvesters and diving into the water to pull the milfoil from its base each summer. Remnants of the weed can re-sow into the lake bottom and produce more mature plants. Other, non-chemical remedies used by the association include snorkel hand-pulling by volunteers, installation of barrier matting on the lake bed, the introduction of a specific variety of water weevil that feeds on milfoil, boat launch inspections, and education programs.
In spite of these dedicated efforts, milfoil has continued to make inroads into the lakes. In 2013, an estimated 3,600 bushels of milfoil were removed from the lake. This number expanded to 5,500 bushels in 2014, according to LDFLA statistics.
“We are not getting ahead; we are falling behind,” Foley said of the milfoil problem.
So the LDFLA made the decision this year to try herbicide over a five-year period. Foley said Renovate has been used with great success in several other Vermont lakes and ponds. The chemical will not harm other plants, fish or swimmers, he said.
“It is safe and highly selective,” Foley said.
But the association would issue advisories to homeowners and recreationists to refrain from swimming in the Renovate-treated areas for 24 to 48 hours after application, Foley said. There could be a second application of Renovate sometime this fall, officials said.
The three regions being targeted are all shallow, mucky and inhospitable to divers. They are also not swept by aggressive currents, meaning the Renovate is likely to stay in place to do its work. And that work should become quickly visible — within around a day or two after application, according to Foley.
“We’re not bombing the whole lake,” he stressed.
Officials are shooting for mid-June, during the middle of a week, for a company to introduce the Renovate, Foley said. That’s when there should be an ebb in the use of the lake by boats, swimmers and kayakers.
State officials will require regular testing of the water to ensure the Renovate is working and is not negatively affecting the health of the lake, officials said.
Estimated cost of this year’s Renovate program: Around $77,000 for Lake Dunmore, and $11,340 for Fern Lake. Future applications would vary based on results. The five-year application permit from the Department of Environmental Conservation would expire in 2020. Foley is very optimistic the permit will be granted.
Association members have been very supportive of the milfoil attack strategy through the years. The LDFLA in 2013 launched a “Lakes Alive — Now and Forever” campaign aimed at raising at least $1.725 million to permanently endow the ongoing effort to clear nuisance aquatic weeds from the two bodies of water. That campaign ultimately netted a very impressive $2 million. But it did not envision a regular herbicide program, so the LDFLA will gratefully accept new contributions to the cause.
Leicester and Salisbury each contribute around $16,000 annually toward the LDFLA milfoil program. The state of Vermont also kicks in around $50,000, according to Foley.
Meanwhile, the LDFLA will continue its non-chemical milfoil fighting efforts. The weed harvesters and divers will be omnipresent on the lakes during what is expected to be a protracted war on an insidious foe.
“Unfortunately, I think this is the natural progression of things,” Foley said. “I don’t think we will ever eradicate it.”
Reporter John Flowers is at [email protected].

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