Eurasian Milfoil Control in Salmon Lake

Introduction

The purpose of this page is to provide a summary of recent past and anticipated actions that address an infestation of Eurasian water milfoil Eurasian water milfoil ( Myriophyllum spicatum ) in Salmon Lake. Check this page again for updates. Eurasian water milfoil is an aggressive invasive species capable of displacing native plants and altering habitat. Found in a six-acre cove on Salmon Lake , it has the potential to spread further into Salmon Lake as well into neighboring water that comprise the Belgrade lake Region and beyond.

Contacts

• For information on DEP Aquatic Invasives Program: John McPhedran, tel. 287-6110.
• For information on Pesticides ( 2,4-D ) Toxicology: Lebelle Hicks, Maine Board of Pesticides Control, tel. 287-2731.
• For information on herbicide discharge authorities: Robert Stratton, Maine DEP Division of Water Quality Management, tel. 287-6114.

Background

The infestation was discovered by a summer visitor in the outlet cove of the lake on Friday, August 1, 2008.  2008 announcement of infestation. Identification of the plant was confirmed on Monday, August 4, 2008 by staff the Maine Volunteer Monitoring Program and Maine DEP's Invasive Aquatic Species Program (IASP).  The IASP initiated Maine 's Rapid Response Plan after confirmation.

The IASP estimates that the Salmon Lake infestation was only one or two years old when discovered.  Maine DEP has attempted to control the Eurasian water milfoil in the cove with diver removal and use of benthic barriers between August 2008 and July 2009. The last three dives of 2009 revealed an increasing number of plants with successive dives culminating in 119 plants on the July 1 dive, the most found in any dive yet. 

Current response

The IASP believes that aggressive response is warranted because the infestation is new enough to control and because of the extraordinary downstream resources at risk with potential habitat for colonization.  IASP staff determined that herbicide treatment is necessary to achieve maximum suppression of the target plant to prevent spread to other waters and to allow the best chance of controlling the infestation in Salmon Lake with manual means. For more information see the 2009 Salmon Lake Public Annoucement.

• A Notice of Intent (NOI) was submitted by IASP to the DEP Division of Water Quality Management on Tuesday, July 28, 2009. A General Permit allows IASP to apply for NOI. This NOI was approved and signed by Commission Littell on Thursday, July 30, 2009. See also the Fact Sheet for the general permit and Human Health Risk Assessment for 2, 4-D*    *Table 3 separately.
• The herbicide product of choice is Navigate, active ingredient 2,4-D. Navigate label; material safety data sheet for Navigate.

IASP is aiming for a late August/early September treatment date. Meanwhile, IASP has contacted immediate residents within 1,000 feet of cove within Salmon lake, Hatchery Brook and its outlet into Hatch Cove with the first of several notices, providing them water use advisories along with a questionnaire regarding water use. A second notice was mailed to residents on September 3, 2009.

Additional materials

• Herbicide results (10/16/2009)
• Herbicide results (10/7/2009)
• September 24, 2009 update concerning herbicide concentration
• Salmon Lake Herbicide Treatment Kozy Cove Herbicide Treatment FAQ September 18, 2009
• Sampling Stations 2009
• Results (9/18/2009)