Milfoil Control

Primary funding for the Milfoil Control program is provided by our Membership Fund.

The Concern:

Eurasian watermilfoil is a non-native aquatic invasive species that forms thick mats in shallow areas of a lake, quickly growing and spreading, killing off native aquatic plants that fish and other underwater species rely on for food and shelter. The plant threatens the diversity and abundance of native plants as well as the ecological balance of lakes and ponds, which in turn adversely affects recreational opportunities. Other concerns are:

  • Creates a barrier leading to nutrient loading
  • Inhibits swimming, boating and fishing near the shore area
  • Negatively affects property values
  • Decaying vegetation leads to unpleasant odors
  • Degrades the lake’s beautiful aesthetics

Our Program:

Since 2007, SLA has conducted the most robust, continuous effort of milfoil control in the Finger Lakes. For the first five years of the SLA Milfoil Control program, SLA reduced the species’ coverage in Skaneateles Lake using hand-pulling and benthic matting methods. From 2012 to present day, the milfoil has been at a “maintenance” control level using just the benthic matting method. Milfoil in Skaneateles Lake will never be eradicated, but we are fortunate our method keeps milfoil manageable.

The SLA Milfoil Control program consists of a lake survey each fall to locate and document large growth patches of milfoil.  The Dr. Robert Werner Research and Education boat (“The Bob”) surveys the lake waters using sonar with GPS along with visual verification from rake tosses to locate milfoil growth. Large growth patches are mapped and analyzed. The discovered growth sites are prioritized by area size with highest priority going to the largest patches with density of 70% or more. In the following spring, Aquatic Invasives, Inc., is hired to “cover” those patches with benthic mats constructed from geotextile material. Each mat is left on a milfoil patch for a minimum of eight weeks to ensure complete elimination. Other factors such as lake depth, slope and stability of lake bottom and boat launch activity are decision factors in matting locations as well. More on the history of milfoil in Skaneateles Lake here.

2023 Results:

2023 matted/completed locations

      • Benthic mats were placed between May 15–Oct. 18, 2023
      • One mat is approximately 12 ft. x 60 ft.
      • 322 total mats were placed
      • The fall survey took 55 hours over 11 days to complete
      • The survey covers 35 miles of shoreline
      • The survey data will be analyzed to create a matting plan for Spring 2024


The SLA Milfoil Control program costs ~$200K annually and is funded by SLA Memberships and other sources, including $30K in Finger Lakes-Lake Ontario Watershed Protection Alliance (FLLOWPA) funds administered by Onondaga County.