A Message from Amy Smagula:
“Relative to the use of aquatic herbicides in “The Meadows” area south of Beaver Lake in Derry, a decision was made by the Department of Environmental Services, Exotic Species Program (DES), to seek a permit for a possible herbicide treatment for variable milfoil control, should one be needed in the 2016 growing season. Variable milfoil is an invasive aquatic plant that can affect the ecological, biological, recreational, aesthetic and economic values of waterbodies. State biologists have been working with Beaver Lake residents to survey and control growths of variable milfoil in Beaver Lake for two summers; unfortunately additional growths were found in the outlet wetland, known as “The Meadows” to the south of Beaver Lake. Like in the lake, variable milfoil growths in the wetland are still relatively sparse, however the hardship lies in the fact that native plant growth is dense, and water depths are shallow, making diving or other non-chemical means of control a challenge in this type of wetland system. A no-control option would result in milfoil expansion in the wetland, and increased risk for further infestation to both upstream and downstream waterbodies. The herbicide treatment is proposed for early June, it is aimed to be selective for the variable milfoil, with few to no non-target impacts. The herbicide of choice is Navigate, which is a 2,4-D ester formulation. It has proven to be the most effective on variable milfoil, and it can be applied at the lower label rate such that non-target impacts are much reduced. This product has been used in a number of waterbodies in NH and beyond, with a good safety record, and good control of the targeted invasive species. It does not persist in water or in sediment, based on data collected by DES biologists in similar sites. DES will survey in the spring to assess the variable milfoil distribution, and will make final plans to treat or not, based on actual site conditions.”
Amy Smagula is a Limnologist/Exotic Species Program Coordinator at NH DES
Download “Long-Term Variable Milfoil Management Plan” for details about the NH Department of Environmental Services plan to mitigate Variable Milfoil in Beaver Lake
Download “Toxicology and Environmental Fate of 2,4-D” a presentation by Bob Reynolds explaining the environmental impact of 2,4-D (the chemical NH DES will use in Beaver Meadow to manage Variable Milfoil found there.) and answering questions regarding health concerns.