Herbicide Treatment Scheduled for Monday on Cobbosseecontee Lake

July 16, 2019

CONTACT: David Madore, Communications Director (207) 287-5842 david.madore@maine.gov

AUGUSTA, July 17, 2019 - Herbicide treatment for a portion of Cobbosseecontee Lake in Winthrop is scheduled to occur on Monday, July 22, 2019 according to the Maine Department of Environmental Protection. The treatment goal is to eradicate Eurasian water-milfoil from the lake. Eradication is difficult to achieve but may be possible since the plant was discovered early in its establishment. The treatment is part of a management plan that includes diver removal of any remaining plants.

The aquatic herbicide Procellacor EC (active ingredient florpyrauxifen-benzyl) will be applied from a watercraft into a 4-acre area of 5,516-acre Cobbosseecontee Lake between Island Park and the mainland were Eurasian water-milfoil was discovered in 2018 and continues to grow. The herbicide application is scheduled to begin mid-morning and will likely take 2-3 hours to complete.

Upon treatment, the DEP will post these advisories for the 4-acre treatment area:

  • Do not use lake water for hydroponic, greenhouse or nursery irrigation before contacting the DEP to confirm the herbicide has dissipated.
  • Do not use lake water for any residential or non-agricultural irrigation (such as shoreline property use for irrigation of residential landscape plants and homeowner gardens, golf course irrigation, and non-residential property irrigation around business or industrial properties) for 3 days following treatment.
  • There is no swimming restriction for florpyrauxifen-benzyl but DEP advises residents not to swim within the treated area for a minimum of 24 hours as an added safety measure.
  • Boaters and jet ski operators are urged to refrain from operating in the treatment area until noon on Tuesday, July 23, 2019 to ensure effectiveness of the herbicide.

Lakeside residents, boat operators and vacationers can help reduce the spread of invasive aquatic plants by boats, trailers, and associated equipment to Maine waters by conducting boat inspections before moving boats between waterbodies. DEP recommends the following:

  • Clean off any mud, plants and animals from the boat, trailer, motor and other equipment. Discard removed material in a trash receptacle or on high, dry ground where there is no danger of washing into the water body.
  • Drain all water from boat, boat engine, and other equipment away from the water.
  • Dry anything that comes into contact with the water. Drying boat, trailer and equipment in the sun for five days is recommended if rinsing your boat, trailer parts and other equipment with hot, high pressure water is not an option.

Learn more about the Invasive Aquatic Species Program by visiting Maine DEP's website at: https://www.maine.gov/dep/water/invasives/index.html#clean