Weed Treatment Plan

Note: Update as of February 2019

Thank you to all who voted for the weed treatment proposal. The results are in and we WILL BE MOVING FORWARD with the treatment! 

For More Information:


To initiate a lake management plan proposed by Solitude Lake Management and discussed at the 2018 annual meeting starting with a treatment utilizing Sonar (fluoridone) herbicide to treat the nuisance weeds found in the lake. The product, Sonar (fluoridone), is a systemic herbicide that works by maintaining a concentration throughout the season achieved by multiple applications, which would need to start at the beginning of the growing season in May 2019.

View Solitude’s Notice of Intent Filing draft here: man_bungaylk18_notice of intent_draft

Is it Safe?

  • There are no label restrictions on recreational activities such as swimming, boating or fishing.
  • It is customary to close the water body during the day of treatment per Solitude company protocol.
  • Sonar is approved for use in drinking water, so it is not harmful to pets or fish.
  • This product is approved for aquatics use by the EPA, as well as the State of Massachusetts, undergone a strict review and has been in use for decades.

The only restriction to note regarding Sonar is an irrigation restriction (meaning if residents are actively drawing water out of Bungay Lake to water their lawn or gardens, this would be restricted while the product has an active concentration in the water).

View Sonar A/S MSDS sheet here.


  • The cost of this project is $54,169 to treat all nuisance areas identified in the lake, see map below.
  • If we target only the higher vegetation areas, all identified areas on the map except the green area, the cost is $39,975.
  • The association can contribute $22,000 from the dues & “FUN”raisers collected over the past several years in preparation for weed control with the members authorization.

To conduct the treatment Bungay Lake Associates Inc. would need to raise the additional dollars, $18K – $33K, prior to May to complete the project if these funds are not raised the project will not be able to move forward and would have to wait until 2020.

How Long Does it Work For?

  • The proposed Sonar treatment should be thought of as almost a “reset.” It will achieve great control of the target invasive species, but eradication is impossible.
  • Solitude recommends this “Sonar reset” to get the system under control and an annual management program after the 2019 season to “maintain desirable conditions.”
  • The ongoing management of regrowth of the target invasive species (fanwort and milfoil) can be conducted at a significantly lower cost, approximately $12,500 per year starting in 2020.
  • Typically, you will expect two to three years of nuisance level control of the fanwort and two years of nuisance level control of the milfoil. Unfortunately, tape grass is affected less and will be diminished during the year of treatment and will bounce back in subsequent years, you could potentially see some benefit in the tape grass control in the year after the treatment.

Tape grass is likely helping limit fanwort and milfoil growth in some of the areas on the eastern and western shorelines and will have to managed in a separate plan not included in this scope/cost.


6 thoughts on “Weed Treatment Plan

    • The weed treatment has been tentatively scheduled for June 8th! Solitude will be posting on the day of treatment and sending emails to those residents on the contact list.

      • In the weeks since treatment has begun we’ve had giant clouds of weeds floating in from the north end of the lake. Notice the legend on the map is all green at the south end cove. We’ve never had these weeds in 26 years. Now the beaches and docks here are surrounded by this muck. There is no swimming thru this stuff , it’s like giant green cotton balls, some as big as a boat. It’s not floating in to shore and it’s not sinking. I can see clumps of this stuff everywhere I look…what’s going to happen?? Is this now taking root and growing ????

      • In response to a question by Board Solitude Lake Management responded:

        “The green clouds you are seeing are filamentous green algae. Filamentous algae is pretty common in all lake and ponds and nothing to be concerned about. The weather this year has made filamentous algae more prevalent in many waterbodies. The reduction of plant growth from the treatment with Sonar herbicide is typically a slow process and does not exacerbate growth, but there could be a small effect this year which should go away as the lake adjusts.”

        Check out more on this algae here ………… https://nature.mdc.mo.gov/discover-nature/field-guide/filamentous-green-algae-pond-scum

      • I don’t believe that!
        This stuff did not grow here. It showed up one morning, then more the next morning, and so on. It’s now overwhelming and I can see it everywhere.
        We’ve had good water here for 26 years we’ve been here. Never once had any of this muck, as the map indicates. Now it’s like pea soup. These weeds are identical to the stuff at the north end of lake and are like icebergs, the real mess is the huge veiny cotton-like mess beneath the surface. Swimming or fishing is not possible. Coincidence with the chemical treatment????? Really…..

  1. We now have GIANT globs of these weeds that have apparently broken free and floated in to the cove at the south end tip of the lake. They look very green as if not dead or dying. Are they going to take root???

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