August 27, 2023, East Andover, NH.  During the July lake water testing event sponsored by the HLPA, variable milfoil was discovered in the outlet channel of Highland Lake in East Andover, above the dam. It looks like it has been there for 1-3 years based on distribution and the fact that some of it is flowering. NHDES Limnologist/Exotic Species Program Coordinator Amy P. Smagula surveyed the entire lake and island shorelines within days, and she determined the growth is just in the outlet, between the boat launch and the dam, though there are a few plants outside of the channel up along the west side.  She did not find anything in the lake proper.

With funding provided by the state, there was a diver lined up to clean it, but after scoping the area, the diver said it was too thick to harvest by hand. Amy is now planning an herbicide treatment for the spring for that area, but there is concern of it spreading into the lake. She also sent an email to Weed Watchers on Webster Lake downstream to be alert to this, and to step up their Weed Watcher efforts.

For anyone on the lake with boats and for people who launch boats at the ramp, the following steps can help mitigate the spread of this invasive weed:

• • Limit boating through the milfoil at the end of the channel above the dam.
  • Take care when boating to avoid the dense beds of milfoil, so they are not chopped up and/or dragged on the propellers into the lake to cause new infestations. 
  • Clean off props before entering the main lake if boating  through milfoil.
  • Be on the lookout for milfoil in the lake and report it via email to: Amy.P.Smagula@nulldes.nh.gov  with address of location.
  •  Spread the word about a spring treatment, possibly with backup diving planned as well, if needed, in other parts of the lake if spread occurs.

The state will pay for management in 2024, but after that, it will need to be a cost share with a local entity like the town and/or shared with other parties.