New weapon vs. milfoil deployed

SALISBURY — Between 8 a.m. and 4 p.m. on any given work day, residents and their guests at Lake Dunmore are likely to see a coordinated team of nine working toward a common goal: ridding the lake of Eurasian watermilfoil (commonly called milfoil), a feathery invasive weed that has been choking Dunmore and its neighbor, Fern Lake, for decades.
The crew has three boats, called suction harvesters, and they collect anywhere between 20 and 100 buckets of the unwanted plant per day.
In recent years, the team’s efforts haven’t been enough to curb milfoil’s ever-growing presence. Last season’s team was 17-strong and worked a combined total of 240 hours per week, but Jim Meyersburg, the head of the aquatic invasive species program within the Lake Dunmore Fern Lake Association, says the team didn’t make a dent.
“We had more milfoil at the end of the season than we did at the beginning,” he said.
That lack of success led the association to employ a new tactic this year: herbicide.
After obtaining a permit from the Vermont Department of Environmental Conservation (DEC) in May, the association employed SOLitude Lake Management to spray two forms of the herbicide, Renovate OTF and Renovate 3 (active ingredient triclopyr) into 80 acres of the lake, in the northern and southern regions, plus an eastern section called “the spine.”
Renovate is designed to mimic a milfoil hormone and kills the weed by interrupting its growth cycle. As far as chemicals go, it’s fairly safe — the conservative 48-hour no-contact bans recommended by the state have long since been lifted, and the water is now safe to consume. Because of the herbicide’s selectivity, it does no harm to native plants and wildlife. The irrigation ban will be lifted in due time at the DEC’s discretion.
Meyersburg said he’s already seeing the effects of the herbicide. In several areas, he’s observed the milfoil keeling over and beginning to shed its leaves — the first steps of a successful treatment.
“It’s doing exactly what (the DEC) said it would do,” Meyersburg said.
Eurasian watermilfoil is a green, leafy weed that can grow in strands up to 20 feet long. In recent years, it has become a major nuisance for swimmers, boaters and fishermen, as well as a threat to native species.
Milfoil is a perennial species and less sensitive to cold temperatures than native plants. It often survives the winter, remaining dormant and growing as soon as light is available. When this occurs, milfoil easily pushes native species out.
Lake association vice president Jim Foley has owned property on the lake for eight years, and he has noticed the unwanted milfoil cropping up consistently.
“Physically speaking, it’s an impediment to swimming, it’s an impediment to propellers, its an impediment to kayakers if it really comes to the surface,” he said. “About this time of the year is when it really starts growing with great vigor because the weather warms up.”
Milfoil’s dense, tangled mats impede water flow, steal habitat from lake-dwelling creatures, trap sediments and add biomass to the lake, a situation that raises the risk of flooding.
Anne Bove, an environmental scientist with the Aquatic Invasive Species section of the DEC, has been working with the association to construct an appropriate response to the milfoil infestation.
“Environmentally, there’s a ton of negatives,” she said of milfoil.
The herbicide treatment will supplement ongoing pulling efforts, which have been part of the lake association’s milfoil program since 1989. Once upon a time, the crew saw success from hand-pulling efforts — and even received an award for environmental merit in 2004 for controlling the invasive plant in an ecologically friendly way.
However, in 2008, an intense rain flooded many septic tanks next to the lake, creating nutrient-rich runoff that may have contributed to an exponential increase of milfoil the next summer. Three years later, the association began using vacuum harvester machines, and in 2015, the fleet grew to four boats, accompanied by the 17-member crew.
The cost of the herbicide treatment subsequently shrunk the crew to nine this summer, but the group still manages to pull hefty amounts of milfoil each day.
A team of three staffs each boat, each with a diver, a “fragger,” who snorkels next to the diver and collects any loose milfoil fragments that fall from the strand, and a shoveler, who tosses the collected weeds into buckets. The fragger’s job is particularly important — any loose pieces of milfoil can fall to the bottom of the lake, re-root and grow. Milfoil is most commonly spread by this fragmentation.
Meyersburg believes that herbicide treatment may actually be more sustainable than hand-pulling.
“We think that the herbicide is a much cleaner and more ecologically friendly way to do it,” he said. “When we’re on the bottom, we’re attacking milfoil, but we’re also attacking natives. We can’t help it.”
Jim Foley doesn’t know exactly when the herbicide conversation began, but the association applied to the DEC for the permit in November 2015, and it was approved in mid-May.
So far, Foley said there has been little opposition to the treatment. Foley oversaw a group of 30 volunteers who notified each household before the treatment began that he stated didn’t hear anything negative from Lake Dunmore residents. Instead, most were grateful that the association was going forward with the treatment.
According to Misha Cetner, in charge of permitting at the DEC, no one requested a public information meeting during the 10-day period when public comments were considered.
However, several residents of Fern Lake opposed the treatment. Meyersburg said their concerns centered on a general skepticism of chemicals and the idea that there may be unknown consequences that result from contaminating the water. Though Meyersburg said he understood the argument, he felt comfortable with the herbicide.
“This particular herbicide has been used for 30 years, all over the country, and absolutely no side effects have been reported by anybody,” he said.
The lake association is a nonprofit, and the invasive species project has an annual budget of $331,057, which comes from the DEC’s grant-in-aid program, the towns of Salisbury and Leicester, and from private donations and dues. Operating costs and wages for suction harvesting add up to around $120,000 annually, according to Foley. The herbicide treatment cost around $95,000.
   JIM MEYERSBURG, RIGHT, head of the Lake Dunmore Fern Lake Association Aquatic Invasive Species Program and Troy Carr, milfoil harvester supervisor, meet up in the middle of Lake Dunmore last week. Harvesters continue pulling the invasive species from the lake after an herbicide was applied to the plants in June.
Independent photo/Trent Campbell
“We didn’t really raise money saying we were going to do herbicide,” Foley said. “So this almost $100,000 expenditure was not a happy undertaking by us because our plan isn’t to spend the money. Our plan is to invest it and let it grow.”
The milfoil program has recently seen a large funding influx. The lake association started the Lakes Alive Campaign in 2010 with a goal of raising $1,725,000, most of which was designated for an endowment. To date, donors have pledged over $2.2 million, and more than $1.5 million has already been collected. 
Around the time the herbicide treatment was applied, the town of Leicester received a $50,000 grant from the DEC. The money will go toward suction harvesting, hand-pulling, herbicide treatment, benthic barriers, and a greeter program in which a lake employee educates visitors about how to use the lake recreationally without spreading invasive species.
In the coming months, the lake association will measure the size of milfoil patches that were treated by herbicide. Though both the association and the DEC are optimistic about the treatment’s effect, neither expect it to result in a total eradication of the species.
“Even if the treatment is deemed successful it doesn’t mean the association’s job is done,” Bove said.
Though the permit for herbicide treatment is valid for five years, the association has not yet decided whether the treatments will continue. The decision will be based on available funds and the measured success of this June’s treatment.
“The permit is fairly flexible in terms of what it allows us to do,” Foley said. “We really don’t take another step until we ask further permission to act under the permit.”
In any case, association members are looking to keep the lakes alive and healthy. In addition to suction harvesters, Meyersburg plans to block off areas where the milfoil reaches the water’s surface and display signs to persuade boaters to stay away.
When plants are near the surface, boaters —  especially those with motors — can chop the plant into the small fragments that fall and re-root. Meyersburg acknowledges that the association can’t order boaters where to go, but the association will advise them.
“We can beg them to please stay away from these areas,” he said.
Though milfoil is currently the only non-native species that has invaded the lakes to the association’s knowledge, they are at risk from others that have struck Vermont lakes, such as water chestnut and zebra mussels. Bove warns those using the lake to clean, drain and dry all equipment to keep invasive species at bay.
Meyersburg and Foley are mindful that the lakes’ health will surely affect future generations.   
“The thing that’s interesting about Lake Dunmore is the history,” Foley said. “Families go back for many generations in these camps. A lot of the folks I deal with now grew up on the lake, or they spent their summers on the lake, or their parents spent their summers on the lake.”
Meyersburg is one of Lake Dunmore’s longtime residents. His grandfather has owned property on the lake since the 1930s. Though he lives in Naples, Fla., in the off-season, he’s been coming to the lake every summer for his entire life.
“That’s the wonderful thing, I find, about the lake,” Foley said. “It’s a succession. I think all of us who work on it hope that we can continue to pass that down.”

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