Herbicide treatment for invasive weeds in Lake Bomoseen draws major opposition

Those opposed to the herbicide treatment have posted signs near the lake. Photo by Emma Cotton/VTDigger

CASTLETON — A debate over the health of Bomoseen Lake has swelled in several Rutland County towns, with residents and leaders at odds over the impact of an invasive weed and a proposal to control it with herbicides.

Eurasian watermilfoil, commonly known as ‘Eurasian watermilfoil’, is a feathery aquatic weed native to parts of Europe, Asia and North Africa. It has grown in numerous lakes around the state in recent decades, including Lake Bomoseen, the largest lake contained within Vermont’s borders at 2,400 acres.

Eurasian watermilfoil can block light from other native plants, eventually crowding them out. The plant can also be a recreational and homeowner nuisance, and its proliferation in a lake can increase the likelihood that it will spread to others on boat hulls or propellers.

Watermilfoil is the most common plant in Lake Bomoseen, according to a investigation of the lake conducted in 2021. Up to 700 acres of the lake are capable of supporting the plant. Climate change is likely to create conditions, such as warmer waters, that favor watermilfoil growth.

Earlier this year, the Lake Bomoseen Association requested a permit from the Vermont Department of Environmental Conservation to expand its Eurasian Watermilfoil management plan, and it included spraying a relatively new herbicide called ProcellaCOR.

Meanwhile, a Facebook group called ‘Don’t Poison Lake Bomoseen’ has gained over 900 members, an online petition titled ‘Keep Lake Bomoseen Chemical Free’ has over 1,300 signatures and a rally against the measure is planned. Sunday outside the City of Castleton offices.

The town of Hubbardton, which was originally on the list of applicants for the permit alongside the Lake Bomoseen Association, removed its name from the application after residents and fishermen spoke out against the plan during a meeting at the end of February.

“We’re asking for a moratorium on spraying herbicides in Vermont waters until we can have a real statewide conversation about how best to handle a way we don’t like” , said Bob Stannard, a former state representative and lobbyist who is organizing the movement against herbicide spraying. (Stannard also writes reviews for VTDigger.)

People who oppose the spraying said the permit application took them by surprise and pointed to the lack of public participation. The app says the lake association plans to start spraying in June – but Sam Drazin, the association’s acting president, said the organization has no plans to spray this year.

“The permit required us to include a schedule,” he said. “It was a proposed timeline because the license required it. We haven’t made any decisions and we won’t be starting this in June. »

Drazin told VTDigger that the association is holding a series of town hall-style meetings to accommodate respectful public discourse and will consider that feedback before making a decision. Stannard said the association’s efforts to understand the public’s thoughts are coming too late, and the organization doesn’t appear to be operating in good faith. He highlighted the organization’s decision to hire a lobbyist.

“You don’t ask the public after you file an application and after you hire a lobbyist without telling anyone,” Stannard said.

Drazin said the lobbyist will help the association identify federal funding that could help Lake Bomoseen more generally, not advocate for herbicide treatment.

“This summer, we’re really focused on continuing the conversations, continuing to build consensus, continuing to learn, what are the community concerns about the health of the lake?” Drazin said.

A frozen Bomoseen lake seen on March 2, 2022. Photo by Emma Cotton/VTDigger

Not an eradication project

Oliver Pierson, Lakes and Ponds Program Manager for the Vermont Department of Environmental Conservation, said state offices have received a number of calls about it. State staffers are reviewing the request, he said, and a formal public comment period will take place before it becomes final.

The state has a responsibility to control and manage invasive species, which the state defines as species that “are not native to Vermont and adversely affect our economy, environment, or health.”

Once Eurasian watermilfoil and other invasive species are introduced, eradication is nearly impossible.

“It’s very, very difficult to eradicate watermilfoil once it’s in place,” Pierson said. “So these are control projects, not eradication projects.”

Pierson said the state encourages non-chemical methods of controlling invasive species, and to obtain its permit, the Lake Bomoseen Association will need to demonstrate that other methods of control will not suffice.

ProcellaCOR has been applied to 10 Vermont lakes over the past two years, Pierson said, and it was effective in killing watermilfoil where it was applied.

“It specifically targets watermilfoil,” Pierson said. “It has very few, if any, off-target impacts. We conduct pre- and post-treatment surveys on plants in lakes, and have found no significant post-treatment impacts of ProcellaCOR on native plants. »

There have been encouraging studies that show the herbicide does not appear to impact insect populations, he said, and that the chemical is “undetectable in waters within 48 hours of the treatment”.

Still, those opposed to the measure cite a number of concerns. Some are concerned about the novelty of the chemical, which hit the market in 2018.

“There are no long-term data on the impacts and effects of this chemical,” Stannard said.

“No wait-and-see approach,” he said. “That’s what we do with all that shit. We put it in the water or we throw it in the ground and then 20 years later we’re like, ‘Oh man, I guess we made a mistake there, sorry about your Parkinson’s. Sorry about your cancer.

Anglers, who say Bomoseen Lake has a healthy ecosystem that supports a diverse and robust fishery, fear the fish have adapted to the weed and its sudden disappearance could affect populations.

Rob Steele, longtime owner of Tom’s Bait and Tackle shop in Castleton, helped organize the opposition movement.

“They claim watermilfoil has issues with recreation for boating and fishing – that’s definitely not the case here,” he said. “The boat ramps are usually full on weekends. You cannot put another boat on the lake. There’s really nothing wrong with that. »

Anglers told Steele that similar applications on other nearby lakes have impacted fishing there, he said.

According to Pierson, the state does not allow herbicide applications on more than 40% of the lake at one time. This limit should allow fish to find suitable habitat when some of the watermilfoil disappears. The data so far does not show that the removal of watermilfoil has had a negative impact on fishing, he said, although he urged fishermen to continue to provide reports.

“Eurasian watermilfoil has both good and bad traits for fishing,” Pierson said. “Too much watermilfoil can take out all the oxygen in the water. It can hamper the movement of fish. It can prevent sunlight from entering.

Pierson spends time on Lake Iroquois in the summer, where the herbicide was recently applied and retreated last year. Anecdotally, he says, it seems the weed disappeared after these treatments.

“What we hope is that it gives native plant species the opportunity to come back and recolonize,” he said.

A general question, Pierson said, is what associations should do if herbicides aren’t keeping watermilfoil away after the treatment cycle ends. The state wants to see lake associations create pesticide mitigation strategies, he said, so they don’t restart the spraying cycle every few years.

When asked if applying the herbicide reduced the chances of the weed returning the following year, Pierson said the state doesn’t know. It’s something they watch, he said.

“It’s not really one of the management goals,” he said. “We’re not bold enough to think this is going to eradicate watermilfoil. We have a very worthy opponent there. We are simply trying to reduce or limit the spread and maintain these uses during the summer months. »

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