Milton Three Ponds update from TPPA

Sharing from Three Ponds Protective Association:
Hello from Maine DEP:
I’m sending this update to an extended email list including NE Pond shorefront owners (for whom I have an email address) and other interested parties.
The herbicide treatment of 41 acres in Northeast Pond was performed by SOLitude Lake Management on July 26. Maine DEP collected water samples for diquat concentration analysis on July 26, 27, 28 and 31. The diquat concentrations have diminished rapidly since the treatment. The latest diquat concentrations are still above the reporting limit, meaning there will be at least one additional sampling round.
The effect of the herbicide was evident on July 28 as most of the floating-leaved vegetation (much of it is little floating heart) within the treatment area had turned brown. By July 31, some of the beds of little floating heart had sunk to the bottom. I expect this has continued to happen with other beds this week.
This result was expected since diquat is not selective and kills both submerged and emergent plants. It causes rapid die-off of the shoot portion of the plant it contacts but is not effective on roots, rhizomes or tubers. The objective of the treatment is to kill European naiad before it sets seed; we are not concerned about the roots because the entire plant dies back each winter.
New England Milfoil (NEM) began removal on July 31 of smaller patches of European naiad in other areas of Northeast Pond. NEM is not working the dense and extensive area they worked last year and there will be some degree of searching involved as they look for relatively small patches previously identified and marked with GPS. Therefore their yield will be lower than 2016 but still critical to the overall plant removal effort. Many of the E. naiad plants NEM is finding thus far are still relatively small and are mixed with natives, making for challenging removal.
Dennis Roberge continues to assist by surveying and marking patches for removal by NEM.
John McPhedran
Invasive Aquatic Species Program
Maine Department of Environmental Protection