By Paul Post
Chemical applications have eliminated Eurasian watermilfoil in problem areas of Saratoga Lake, saving considerable money and providing better recreational conditions for boating, swimming, fishing and paddle sports, which contribute to the local economy.
“Milfoil rapidly takes over a lake,” said Cristina Connolly, Saratoga Lake Protection and Improvement District executive director-administrator. “Years back this lake was pretty much all milfoil. It was so bad you could almost walk across the lake. It out-competes the native plant species and native wildlife and their habitat.”
But in 2020 and 2021, the district hired a private firm to treat the worst sites (54 and 32 acres, respectively) with a chemical called ProcellaCOR, which has been used in hundreds of lakes throughout the country since the U.S. Environmental Protection Agency approved its use in 2017.
“It was very successful and we have not needed to do another treatment since then,” Connolly said. “It targeted the milfoil and allowed the native plants to thrive and out-compete any milfoil that was there. To this day we do regular vegetative assessments and one large annual one where we hire a consultant. Milfoil is now minimal. There was no reason to do another treatment this year. We’ve been very, very happy with it.”
Small patches of milfoil are still present in some places, but not large enough to warrant additional applications. “But we keep our eye on it,” Connolly said.
ProcellaCOR, manufactured by Indiana-based SePro Corporation, kills plants with a hormone that plants absorb, causing them to grow too rapidly and die off within a few weeks. Plants turn brown, stems swell up, burst, fall over and rot.
The optimal time is mid-May to mid-June when plants are large enough to absorb the chemical, but still small enough to avoid a huge biomass of dead plants on the lake bottom.
Treatments are much less costly and are more effective than DASH (diver assisted suction harvesting) programs and mechanical harvesters, and faster acting than herbicides such as Sonar, which may take up to 90 days to kill the nuisance aquatic weed.
The state Department of Environmental Conservation approved ProcellaCOR’s use in 2019. It was first used in the Adirondacks at Minerva Lake a few years ago and it’s been applied to several other Warren County water bodies such as Lake Luzerne, and Lake Sunnyside and Glen Lake in Queensbury.
In late May 2023, the Town of Luzerne spent $36,000 for an application around Lake Luzerne’s perimeter, a $16,000 savings from the previous year’s $52,000 DASH project, which must be done annually as milfoil grows back. The town saved another $52,000 this year because milfoil has been almost totally eradicated.
Deputy Supervisor Jim Niles, who has a degree in environmental science, oversees the town’s milfoil management program.
“From a performance standpoint we’re very, very happy,” he said. “We haven’t seen any negative side effects. There’s been no damage at all to native plant species that we can tell. Divers say the fish community looks the same.
Divers did a video in early July and found two live milfoil plants, very small ones.”
A series of tests at multiple sites, following treatment, determined that ProcellaCOR’s compounds had completely broken down and weren’t detectable in the water after 24 days, he said.
The main reason for combating milfoil is its impact on the environment and ecological systems. But there is a definite economic benefit, from a recreational tourism perspective as well, Niles said.
“It’s hard to put a number on it, but we think it would be huge if we didn’t take care of that lake especially for a small town like ours,” he said. “The loss of just 100 tourists is significant.”
“It really was a risk-benefit decision,” Niles said. “The benefit list was pretty obvious and pretty long. We had no known risk. It was really a no-brainer.”
But not everyone is convinced about ProcellaCOR.
The non-profit Lake George Association waged a lengthy legal battle, trying to prevent the Lake George Park Commission from using the chemical, which was finally applied this year at Blair’s Bay and Sheep Meadow Bay. Both sites are in northern sections, on the east side of the lake.
The LGA and Park Commission have worked closely over the years on many fronts to protect the lake from various threats. The LGA contributes $140,000 each year to a roughly $400,000 milfoil containment program using divers. This is the first time an herbicide of any kind has been used to combat the weed in Lake George.
LGA Waterkeeper Chris Navitsky has concerns about ProcellaCOR’s effectiveness in Lake George and alleged potentially harmful side effects.
“First of all it’s not a crisis, milfoil is not taking over the lake,” he said. “It’s not preventing recreation. There has been an effective management tool (DASH) for a number of years. There’s no need for a drastic change.”
And unlike relatively quiet and much smaller Saratoga Lake and Lake Luzerne, even the bays within Lake George have significant currents, which could carry ProcellaCOR beyond treatment zones before it kills milfoil.
Navitsky said most tests on ProcellaCOR during the EPA’s approval process were done by the manufacturer in controlled laboratories rather than real-world conditions.
“This has only been around for seven years,” he said. “It takes time for studies to be done properly. The EPA did not confirm that this was a selective growth hormone. Some research is starting to come out that says this does have impacts on native plants. It clearly does kill milfoil. We aren’t doubting that. But since it is a growth hormone it’s taken up by all vascular plants and some non-vascular plants. There could be impacts to native plants and macro invertebrate animal communities.”
In small doses, those less than approved treatment levels, ProcellaCOR could actually act like a fertilizer and contribute to milfoil growth if the chemical migrates to other parts of the lake, he said.
But Park Commission Executive Director Dave Wick said there is no scientific evidence to support such claims. He said this year’s treatments have been highly effective at killing off milfoil at considerable cost savings.
The Commission will continue its DASH program and complement it next year with ProcellaCOR at high priority sites where milfoil is densest, possibly Sunset and Harris bays, he said.
The chemical has been approved by the EPA, DEC and Adirondack Park Agency and there are no restrictions for its use related to drinking water, swimming, fishing or lawn watering, Wick said.