Treatment of Eurasian Watermilfoil in Findley Lake

Treatment of Eurasian Watermilfoil in Findley Lake

The Findley Lake Watershed Foundation will be employing a new strategy in our fight against Eurasian Watermilfoil, a non-native weed that has invaded our lake. Herbicide treatment has not been an option in our arsenal for invasive plant species until the approval of ProcellaCOR EC (florpyrausifen-benzyl) by the USEPA in 2018 and NYSDEC in 2019 (NYUSDOH, Division of Fish and Wildlife).

ProcellaCOR EC – A selective Systemic Herbicide has limited non-target impacts, rapid plant uptake (2-6 hours), low dosage (<8 parts per billion) and fast degradation (Photolysis). The active ingredient Florpyrauxifen-benzyl mimics the plant growth hormone – causing uncontrolled rapid growth that ultimately kills the plant. Plant death and decomposition will happen within 2-3 weeks.

Lake water use restrictions will be in effect for the period indicated in the table below.



Signs will be posted at public access sites around the Lake notifying users of the water use restrictions. When all water restrictions are lifted, posted signs will be removed.

Eurasian Watermilfoil is an invasive, non-native aquatic plant. It has caused economic and environmental harm to our community due to the large beds of milfoil that impair the recreational use of our waterways and degrade the native habitat for fish and other wildlife. It has no native predators, it grows well in disturbed areas, each plant can produce 100 seeds per season, and it’s much more successful at vegetative reproduction via fragments and runners. After flowering, this species can undergo auto-fragmentation where fragments are then transported via wind, waves and human activity.

In September of 2023 Adirondack Research conducted an aquatic plant survey of the entire lake. From this report we have developed a well-thought-out plan to reduce the amount of Eurasian Watermilfoil. On April 19, 2024, we received DEC approval to treat approximately 41 acres of Eurasian watermilfoil. The areas shown in the below map, on the north end of the lake (the end closer to town) will be treated on May 30, 2024 (rain date May 31, 2024) The objective is to minimize and possibly eliminate these dense weed beds, and greatly enhance the usability of the lake.

Prior to the DEC approval, a Letter of Notification was mailed on February 22, 2024 to all home owners with land directly bordering lake and they were given 21 days to contact the NYSDEC with any objections. 

While there are also extensive watermilfoil weed beds in the southern portion of the lake, we decided to focus on the northern end of the lake (the half closest to town) this first year to enable our weed harvester to be more efficient in harvesting weeds primarily in the southern portion of the lake. In years past, a considerable amount of time is spent traveling to harvest weeds on the northern portion of the lake.

Ready Scout, LLC, our consultant for this project, has conducted a pretreatment survey of the lake on April 26, will treat the areas approved by DEC on late May 30 and will conduct a post treatment efficacy survey in August.

We will be using our website, email distribution list and our Facebook page to keep the community informed on any changes to the schedule. Emails are sent to members of the Findley Lake Watershed Foundation only, please visit our website to become a member and/or verify we have your correct email address.

Figure 1. Map showing Eurasian watermilfoil weed beds in the northern half of Findley Lake (half closest to town) with the DEC-approved treatment areas (courtesy of Ready Scout, LLC)