Use this spring of an aquatic herbicide that targets invasive Eurasian milfoil on Saratoga Lake has been more effective than expected, lake district and state officials said Wednesday.
“It’s a huge success, much better than expected,” said Edward Dweck, a member and past chairman of the Saratoga Lake Protection and Improvement District.
Aquatic Control Technologies Inc. of Sutton, Mass., applied 66,920 pounds of the herbicide Renovate OTF along the eastern shore of the five-mile-long lake between May 27-30.
The active ingredient in Renovate is triclopyr, which is effective in killing milfoil but not the other necessary native weeds in the lake.
This $300,000 application of herbicide is the second year of a three-year program to reduce or eliminate the invasive Eurasian milfoil. The first application of a chemical called Sonar was done in 2007 at the south end of the lake.
The milfoil spreads out on the lake surface, especially near the shoreline, almost like a rug, preventing boating and swimming.
The lake district has waged a battle against the milfoil for more than a decade. It has used, and continues to use, large, floating weed harvesters since the 1980s to cut weeds around the lake.
Timothy Sinnott, a biologist with the state Department of Environmental Conservation, said the state was pleased to give the lake district a $95,000 grant toward the project.
He said DEC views a lake as “damaged” when Eurasian milfoil starts infesting the shorelines.
“We are really excited to see Renovate come on the market,” Sinnott said during a boat tour of the eastern shore of the lake Wednesday afternoon. The chemical finally passed review and was permitted to be used in the state just last fall.
Neither Sonar nor Renovate have any negative impacts on humans, fish or other wildlife, according to the authorities.
Dean Long of the Saratoga Springs-based LA Group, which has done a watershed study of Saratoga Lake and is a lake district consultant, said the use of Sonar at the south end of the lake last year has also kept the milfoil out of the lake this year.
Long said lake specialists generally maintain that the chemical applications are good for about three years. Then lake monitoring is done and milfoil inventories are taken so that “small retreatments” of the herbicide can be made at places where the invasive species has returned.
The lake district and its consultants are currently doing inventory and monitoring work on the west side of the lake, in Saratoga Springs and Malta, to prepare for the third and final Renovate application in 2009.
The first use of chemical herbicides in Saratoga Lake was in 2000, when test applications were made.
The 2007 application cost the lake district about $225,000 and the west side application will be about the same, according to Marc Bellaud, a senior biologist with Aquatic Control Technologies. He said the east side of the lake in Saratoga and Stillwater included 300 acres of milfoil and was a larger area than the southern end of the lake.
Mark Heilman and Sarah Miller, both representatives of SePRO of Wilson, N.C., the company that provides the Renovate, have also done work on the lake monitoring weeds, especially the remaining milfoil on the lake’s west side.
Aquatic Technologies used two boats to spread the granular Resonate in May. It took the boats four days to spread the material using GPS devices on both boats.
Long of the LA Group said the net effect of the Renovate is that the native lake weeds remain and there is “virtually no milfoil” in the application area.
Joseph Finn of the town of Saratoga, a longtime lake district commissioner, said he appreciated the successful work done by Long, Aquatic Control Technologies and SePRO.
The lake district was created in the mid-1980s by an act of the state legislature to protect and improve the lake. Residents living around the lake pay special district taxes that fund the work of the weed harvesters and the chemical applications.
Milfoil was first spotted in the District of Columbia in the 1940s and is usually spread from one lake to another by boating activity, according to the state of Washington’s Department of Ecology Web site.