During an early September plant survey in 2020, a volunteer plant patroller found a suspicious plant in Androscoggin Lake’s Inner Cove that was confirmed to be variable-leaf watermilfoil (VWM), an aquatic invasive plant. Since 2021, 30 Mile’s consistent survey and manual removal work have successfully contained VWM to the Inner Cove, with just 12 plants found in 2025. While our management efforts have been effective, there remains a significant risk that the plant could spread to other parts of the lake, increasing its ecological, economic, and recreational impacts, as well as long-term costs of management. Given the small size and limited extent of the infestation, using an herbicide treatment now will greatly increase the likelihood of eradicating VWM.
The Maine Department of Environmental Protection (MEDEP) has proposed an aquatic herbicide treatment using ProcellaCOR EC to address the invasive VWM. The use of ProcellaCOR EC has proven effective in controlling VWM in other Maine lakes, including in the nearby Belgrade and Cobbossee watersheds, while being low risk to human health and native plants and animals.
The treatment was originally planned for July 1st, but due to the permit application still being under review, the treatment has been postponed. Once approved, MEDEP will notify property owners within 1000 feet of the treatment area of the new date.
For more information and updates as they become available, please visit our website.
Photo: DEP and 30 Mile staff conducting pre-herbicide treatment survey in June 2026
This article was included in 30 Mile’s June 2026 newsletter. To view the full release, click here.