Milfoil Control

What is Eurasian Milfoil?

Eurasian Water-milfoil is commonly called Eurasian Milfoil, and for brevity is frequently referred to as simply milfoil on this website. It's botanical name is Myriophyllum spicatum. It is a submersed aquatic plant native to Europe, Asia, and northern Africa. The plant was introduced to the United States around 1940, and has spread throughout much of North America.

Generally found in water 3 to 10 feet deep, milfoil reproduces extremely rapidly, and can infest an entire lake within two years of introduction by forming thick underwater beds of tangled stems and a vast canopy mat of vegetation at the water's surface.

The plant can take over a lake rapidly due to it's ability to store more nutrients in it's roots than native plants. This results in it being able to sprout early in the spring, allowing it to block the sunlight needed by other plants to sprout.


Northern Milfoil     Eurasian Milfoil

Identifying Eurasian Milfoil

Eurasian milfoil has slender stems encircled by feathery leaves in groups. It can be difficult to identify for the casual observer because you are typically looking down at the plant in the water, and if you break off a stem to get a better look it appears quite different from it's appearance in the water.

The photograph above is a good representation of how it would appear in the water if you were observing it wearing a diving mask. The right-most plant in the photograph to the left shows what it looks like when removed from the water

Northern milfoil, which is a native, non-envasive plant, closely resembles Eurasian milfoil, and can also be found in Brant Lake. It can be distinguished by the number of leaf divisions; Eurasian milfoil has 9-21 pairs of leaflets per leaf, while Northern milfoil typically has 7-11 pairs of leaflets. Another technique for telling the two apart is that the feathery leaves of Eurasian milfoil collapse when removed from the water, while Northern Milfoil leaves remain firm. The photograph on the right illustrates this difference.

How Eurasian Milfoil Spreads

Milfoil is introduced to a body of water by stem segments that are transported from another infected body by boats, trailers, bilges, live wells, or bait buckets, where they can stay alive for weeks if kept moist. Waterfowl may also play a part.

Although milfoil produces many seeds, it's seeds germinate poorly, and most increase and spread of the species is the result of fragmentation. In the late summer and fall the plants become brittle and naturally break apart. These fragments can float to other areas, sink, and start new plants. Once a plant is established in a new area, it spreads locally from runners that creep along the lake bed. Milfoil reproduces extremely rapidly and can infest an entire lake within two years of introduction.


Captured! An Eurasian Milfoil fragment looking for a new home in Brant Lake

This milfoil fragment was removed from the lake in September 2008 during a mat laying effort.

It was one of many, floating near the surface, being carried by the current at a moderate pace on a quest for a hospitable environment to establish a new milfoil colony; perhaps just off your beach.

This is a mean, green, reproduction machine! We have a formidable foe.

Locations On Brant Lake Where Milfoil Was Found and Removed in 2012


Milfoil in New York State

Eurasian Milfoil Infestation in the United States


Controlling Eurasian Milfoil

While it is thought that it is impossible to completely eradicate milfoil once it has been established in a body of water, there fortunately are measures for keeping it under control. Unfortunately, these measures are either expensive, illegal, or unadvisable.

Here is a summary of the various methods. A detailed description of each method follows.

Milfoil Control Techniques Not Appropriate for Brant Lake

Milfoil Weevil

Use of this small aquatic weevil is very appealing, since it is native to the US and prefers dining on Eurasian Milfoil over other vegetation. There appears to be some spotty success stories with using this insect, and there is a company, EnviroScience, that specializes in treatment using this weevil. Unfortunately, there is currently no understanding of why it has shown to be effective in some lakes but not others. As academics like to say, "More studies are needed". We are monitoring the developments in using this technique. More information on weevils can be found here.

Herbicide Control

There are herbicides, such as Sonar and its more modern cousin Renovate OTF, that can be used to control milfoil. However, the chemicals are very expensive, and often need to be repeated every few years, as has been the experience at nearby Glen Lake. More significantly, while use of herbicides to control milfoil within the Adirondack Park were for the first time approved in 2010 for use in Lake Luzerne, it was a very carefully controlled experiment under relatively ideal conditions. Those conditions would be impossible to replicate on Brant Lake, and thus approval for use on our lake is currently extremely improbable. Scratch herbicides.

Milfoil Control Activities on Brant Lake

Public Education

  • Milfoil related presentations are regularly given at the two annual BLA meetings, which are open to the public.
  • A well-publicized community-wide milfoil informational meeting was held in 2008.
  • A Brant Lake Milfoil Control web site was established in 2009 for public education and volunteer coordination.
  • An informational bulletin board was placed at the public boat launch in 2009.
  • A Milfoil Control Program brochure was developed In 2009. It was delivered to lake residents door-to-door and placed in 34 commercial establishments in the greater Brant Lake community.
  • "Clean Boats, Clean Waters" bumper stickers were developed and distributed in 2009.
  • Informational mailing on milfoil control activites sent to association members in 2009.
  • An Aquatic Plant Invasive Identification Training session held at the Town Hall in 2010

Fund Raising

In 2009 a major three year fundraising campaign was initiated.

  • A community-wide kick-off meeting was held at the Town Hall.
  • Over 30 volunteers conducted a lake residents door-to-door campaign to distribute information about the campaign.
  • Area businesses and significant donors were personally solicited by the Finance Committee.
  • A mailing was sent to all BLA members.
  • Generous donations were made by many area businesses, including: Able Energy, Gallo Realty, Smith's Plumbing, Adirondack General Store, Glens Falls National Bank, Stewarts, Brant Lake Camp, North Country Auto Repair, Sunset Mountain Lodge, Brant Lake Taxi, Palmer Bros. Marina, Buchanan & Butler, and Paraco Gas Co.
  • A Milfoil Fund Raising Phonathon was conducted.
  • With donations and pledges the $250,000 three year goal was met!

Significant financial support has also come from the Town of Horicon, which has contributed:

  • 2012 - $20,000
  • 2011 - $40,000
  • 2010 - $40,000
  • 2007 - $5,000

There is also an on-going effort in grant applications and donations from local businesses. Successes to date are:

  • In 2011 the following local businesses made significant contributions: Stewart's Shops - $500, Jacob & Toney - $100, Gallo Realty - $125, Chestertown Grand Union - $100, Glens Falls National Bank - $500, Price Chopper - $250, International Paper - $1,300.
  • $500 from Dake Foundation (Stewart's) in 2009
  • $10,900 Invasive Species Grant in 2005.

Record Keeping

A key to fighting milfoil is to have in-depth knowledge of each bed in the lake. Numerous activities at our lake have contributed toward satisfying this need.

  • All information is logged into a milfoil spreadsheet. This is a significant, ongoing effort. Information tracked is:
    Bed location, determined by GPS
    Yearly history of the bed
    Number of mats (if any)
    Date last inspected
    Next action to be taken
  • The spreadsheet information is uploaded to the milfoil control website and is available for viewing in a variety of forms:
    Raw data
    Map showing location of beds. Clicking on a bed location displays the detailed information for that bed.
    Map showing location and number of bottom mats in place.
  • A dedicated hot-line telephone number is available to report a milfoil bed discovery. All reported beds are investigated and added to our spreadsheet if they are new. Numerous new beds have been reported using either this number or email.

As of 2009 32 milfoil beds have been documented.

2010 Update: The company we hire for milfoil control, AIM, added the facility for divers to communicate with surface personell, allowing them to dynamically map locations where milfoil was found and removed. Additionally, as of the end of 2010 all known infected areas were milfoil free. Thus we are no longer maintaining a map of milfoil locations. However, the data and map of unremoved bottom mat locations is still in use.

Bottom Matting

Lake bottom mats, also know as benthic barriers, are fabric materials that are placed on sections of the lake bottom by divers and held in place with weights. They are legal for use within the Adirondack Park. This is a labor intensive but effective method for controlling milfoil. Benthic mats are particularly useful in treating small to moderate sized patches of dense growth. The barriers are used to reduce light levels and inhibit growth of vegetation. While matting kills all plant species indiscriminately, in colonies where matting is used milfoil has typically already crowded out the other species.

This operation requires mats and divers to place them. Fortunately, using volunteers we have been able successfully implement this technique at minimum costs.

While there are commercially available mats intended for this purpose, they are very expensive. We have devised a simple and cost effective technique for using volunteers to build these mats using heavy duty tarps and rebar (steel rods). The tarps are unfolded, holes are strategically punched, and the rebar is woven though the mats. The rebar is then tied at the edges with nylon tape or cable ties. The rebar serves as weights to hold the mat to the bottom, and the holes also serve as vents to allow gas to escape as the covered vegetation decays.

In 2009, 34 20′x35′ mats were constructed. This is approximately a half-acre of material! All 34 of the mats were placed on the bottom by our volunteer teams.

Our divers place the mats on the lake bottom directed by GPS coordinates in our milfoil bed database. This is typically a difficult job, since the mats are heavy, there are numerous obstacles of rocks and stumps on the bottom, and the divers frequently have to work by feel because of stirred up sediment. Volunteer surface workers must also be used to collect any milfoil fragments that result from the activity. All operations must be carefully entered into the milfoil database so that the mats can later be located and removed after they have done their job. They may then be re-used in another location if their condition permits.

In 2011 the mats have done their job, and with milfoil now under control in the lake there is a major undertaking to remove the mats to allow native vegetation to return.

Hand Harvesting

Hand harvesting of milfoil is also allowed in the Adirondack Park. It is similar to weeding in a garden, with the difference that you are working underwater with very limited visibility due to stirred up sediment. Divers uproot individual plants and either put them in a mesh bag or use a suction tube to transport them into a boat. Special care must be taken to ensure that the entire plant (leaves, stems and roots) is removed. This is an extremely labor-intensive operation, and at Brant Lake our volunteers diver are only able to handle a small portion of the work that has needed to be done. This requires us to hire professionals to do the bulk of the work, at considerable expense. Our expenses to date are (roughly):

  • 2009 - $100,000
  • 2010 - $85,000
  • 2011 - $50,000
  • 2012 - $35,000 (projected)

Volunteer Hand Harvesting

When milfoil was easy to find in the lake we used a pool of 10 volunteer divers to do a limited amount of hand harvesting, As is 2009 this activity has been discontinued.

Professional Hand Harvesting

Aquatic Invasive Management (AIM) was formed by Andrew Lewis and Tommy Thomson, alumni of the Paul Smith's College of Natural Resources. The BLA first contracted with AIM in the fall of 2008. Prior to selecting AIM, members of the Milfoil Committee searched the internet, consulted with the Adirondack Park Council, and networked with milfoil committees from Loon Lake, Schroon Lake, and Saranac Lake. The committee in Saranac Lake was the most experienced at milfoil control, and several years ago they chose AIM to assist them with their efforts. The AIM organization has extensive experience and they have made tremendous strides toward controlling milfoil in Saranac Lake. In addition, they have done milfoil removal on Minerva Lake and Lake George.

AIM has developed two approaches to milfoil removal. In low density areas an 8-diver team operates in a line formation over a wide geographic area to remove scattered plants and small beds. This approach has the support of a 2-person crew and is able to cover large areas efficiently. For high density areas a 10-member crew utilizes eight divers inside a series of nets erected around the harvest site. This allows for plants to be pulled out at their roots, but rather than bagged individually, plants float to the surface within the netted area and are transferred into boats for transport to shore by the above water team. These techniques have allowed AIM to maximize the effectiveness of hand harvesting for both high and low intensity sites. Additionally, these techniques allow the divers to breath using individual air lines supplied by a single compressor on a floating platform, which is much more efficient than requiring each diver to use individual air tanks.

In 2009 AIM added the capability of communication between the divers and the surface crew, allowing them to created detailed maps of where milfoil was found and removed.

Milfoil Control History on Brant Lake


Milfoil first reported in the US. It is believed to have been carried in the bilge of a ship originating from Asia.


Milfoil first reported in Brant Lake.


Mickey Butler leads successful effort to raise $15,000 to purchase mats and a hire professional to install them along the shoreline opposite Mead\'s cottages, covering an area of 100′x150′. They would remain in place for 9 years.


  • Brant Lake Watershed Assessment completed
  • Aquatic plant survey conducted by the Darrin Freshwater Institute


Mats placed in 1994 moved to a site near Big Rock, unfortunately damaging the mats. Family of divers hired from Horicon Birches to spread the moved mats, with limited success.


Brant Lake Association becomes an tax exempt 501(c)3 organization, enabling future milfoil fund raising efforts.


  • First "experimental" attempt at hand harvesting. The target was two dense beds near near Sunset Mountain Lodge using 3 divers and 15 other volunteers. Results were satisfying and much was learned.
  • Received a $10,900 invasive species grant with help from Betty Little.
  • Received a $15,000 grant from NYS for a septic pump-out program. The approximately 85 participants received a $75 rebate for the volume discounted pump-out cost.


Two beds near Sunset Mountain Lodge that were hand harvested last year were checked again this year. They had grown back to about 80% of their original size. Due to various factors no hand harvesting was done this year.


  • Town of Horicon provided $5,000 towards milfoil control.
  • Had about 20 working days making and laying mats and doing hand harvesting. Approximately 40 different volunteers were involved.
  • Identified 20 beds covering more than 10,000 square feet. Successfully addressed 19 of the 20, leaving them about 80% under control
  • Established a volunteer program, "Head-a-Bed", for monitoring the status of identified beds
  • Established a special phone number to report a bed you have discovered
  • Established a milfoil bed location database based on GPS data. Locations are displayed on a map on the BLA website


  • Established three-year $250,000 plan for community-wide fundraising for 2009
  • 20 new milfoil beds identified and mapped. The new growth represents over 20,000 square feet
  • Volunteer teams focused on the dense and large milfoil beds in the Sunset Mountain area between Point O\' Pines Camp and the Brant Lake Farm beach. Also harvested and placed mats over a large area near Grassville Road
  • Added all new beds to database, which can be seen on the website milfoil map
  • Established successful working partnership with Aquatic Invasive Management
  • Created an on-line milfoil Yahoo Group to coordinate volunteer activities
  • Purchased a glass bottomed kayak to assist with the finding and monitoring of the milfoil beds
  • Established Brant Lake Community Awareness Program


  • Community milfoil informational meeting held at the Town Hall
  • Developed and distributed bumper sticker, "Clean Boats, Clean Waters"
  • Milfoil Control Program brochure was developed. It was delivered to lake residents door-to-door and placed in 34 commercial establishments
  • Held orientation for volunteer scuba divers. Now have 10 volunteer divers.
  • Volunteers constructed 34 mats at significant savings.
  • Volunteers hand harvested 32 milfoil beds - 10 new and 22 existing.
  • Volunteers placed 34 bottom mats.
  • AIM crew of 8 divers plus 2 surface crew completed 6 full weeks of activity. Removed over 5 tons of milfoil!
  • Lake residents reported 10 new milfoil beds through the milfoil hotline or email. To date have documented 32 milfoil beds.
  • Informational bulletin board placed at public boat launch
  • Conducted Milfoil Fund Raising Phonathon.
  • With donations and pledges the $250,000 three year goal was met!!!


  • Aquatic Plant Invasive Identification Training session held at the Town Hall
  • Again hired Aquatic Invasive Management for 5 weeks of hand harvesting with 8 divers. Removed over 4 1/2 tons of milfoil! The coat was $85,000, with $40,000 contributed by the Town Reached the goal of maintenance mode, which should significantly reduce future hand harvesting expenditures.


  • Initiated a monitoring program at the NYS public boat launch. Two local high schools students attended a training session at Paul Smiths College and spent their summer weekends on duty at the launch, providing boater education and performing voluntary inspections of over 400 boats. Funding was provided by the Town.
  • Again hired Aquatic Invasive Management for 7 weeks of hand harvesting, with 4 divers for 2 weeks and 2 divers for the remaining 5. Found only about 1/2 ton of milfoil to remove, compared to over 4 1/2 tons in 2010 and 5 tons in 2009, confirming that we are indeed in maintenance mode. The cost was $50,000, of which $40,000 was contributed by the Town
  • Established a Shoreline Monitoring Program. The lake was divided into 10 mile sections, with a volunteer to monitor each section, reporting periodically through this website.


  • Again hired AIM for hand harvesting, at a cost of $35,000. The Town contributed $20,000 toward the expense. 4 weeks of swimming the complete perimeter of the lake multiple times yielded only 5 bags of milfoil. Unfortunately, during the 5th week a new bed was discovered, which brought the bag-count up to a total of 35 for the year.
  • Boat launch monitoring was expanded to cover most Fridays


  • AIM was again hired for 4 weeks with a three person crew, at a cost of $28,000. The Town contributed $20,000 toward the expense. New pockets of thick milfoil growth in the far lower end of the lake were discovered. 22 bags of milfoil were removed.
  • BLA volunteers removed another 12 mats and installed 1 mat in the area of Mead\'s Cottages. There are now 34 mats remaining at 11 bed locations in the lake.


  • New mature beds were discovered yielding 157 bags during 4 weeks of harvesting by AIM. This was a significant setback, with a 36% increase from the previous year.. A 5th week was added. 3925 pounds were harvested, with the total cost at $38,000, with $26,000 provided by the Town.
  • 20 mats removed by volunteers, leaving only 16.
  • Began 2 year Lake Management Program with SUNY Oneonta.
  • Boat Launch inspection hours increased with funding from the Town
  • Brant Lake Strategic Plan finalized.


  • The association and the Town together agreed to turn over the management of milfoil control efforts to environmental professionals working for the Warren County Soil and Water Conservation District. Funds will flow to the County and then on to the professional divers. There will be no charge for this management.
  • 6 weeks of harvesting yielded 5900 pounds of milfoil, The large harvest coincided with similar experiences in many other lakes this season. The combined harvesting cost to the Town and Association was $37,400.
  • Increased Town funding allowed expansion of the on-duty hours of the Lake Stewards at the boat launch.
  • With hand harvesting determined to be, in general, a control technique superior to bottom matting, efforts continued to remove mats put in place years ago by our volunteer divers to allow the native vegetation to return. This is a very difficult and labor intensive task. A custom hoist mounted on a platform boat was designed to help remove the very heavy weighted mats from the water. Volunteers removed 6 mats, leaving only 10 remaining.


  • An initial 5 weeks of harvesting yielded 5135 pounds of milfoil and 50 pounds of Curley Leaf Pond Weed. Based on the high yield and known remaining milfoil, 2 more weeks were added to the schedule, yielding an additional 2200 (+ week 7) pounds. This was a 38% increase from the previous year. The combined harvesting cost to the Town and Association was $51,610.
  • Increased Town funding allowed expansion of the on duty hours of the Lake Stewards at the boat launch to 7 AM to 6 PM Memorial Day to Labor. Collected data is entered into a tablet and uploaded to Paul Smiths College, where it is merged into an area-wide database for analysis.
  • Efforts continued to remove the remaining mats from the lake bottom. A new removal technique of first removing the rebar woven into the mats was successfully used.