Les Cheneaux Islands Eurasian Watermilfoil Control

Funded through the US EPA Great Lakes Restoration Initiative (GLRI), grant number GL-00301928-0, 2016-2018.

Final Report - GL-00E01928-0


This project implemented a medium-scale (up to 10 acres/year) biopesticide treatment using the indigenous fungus Mt and other techniques for control of invasive Eurasian watermilfoil in the Les Cheneaux Islands of Lake Huron. Treatment outcomes as well as longer-term effects of previous releases of the fungus and a milfoil weevil were evaluated using field surveys and multi-scale remote sensing and mapping across an 800-acre area, and shared through outreach. The project helped promote public recreational opportunities in an area where they have high economic value and improve ecosystem function by restoring and retaining native aquatic vegetation species.

Responding to the local community’s strong preference for avoiding commercial herbicide use at the scale that would be required to control the area’s nuisance EWM (and the approx. 120 potable water intakes currently used by area residents, which present an obstacle to chemical herbicide application), and building on previous work testing and developing EWM biocontrol methods at this site, Michigan Tech University (MTU) and the Les Cheneaux Watershed Council (LCWC) aimed to continue implementing and evaluating EWM biocontrol techniques. We proposed an adaptive management approach that evaluates the performance of the treatment technique established for control of EWM using the fungal pathogen Mycoleptodiscus terrestris (Gerd.), or “Mt”, an indigenous organism not altered by genetic engineering. The use of adaptive management built from the current GLRI project (completed late 2015), “Arresting the spread of Eurasian watermilfoil in Lake Superior” (GL-00E01291-0), led by PI Dr. Casey Huckins, who is a Co-I for this proposal.

The extent of benthic cover by EWM as well as other macrophyte species was comprehensively mapped using field surveys and high-resolution, multiscale remote sensing. Mt treatment plots totaling up to 10 acres of EWM beds was established each year within the approximately 800-acre area of Cedarville and Sheppard Bays. Analysis of the differences between treatment plots and in the environmental conditions at the time of treatment application helped clarify the conditions that favor EWM susceptibility to Mt. Outputs included a revised and expanded Les Cheneaux Dynamic Aquatic Adaptive Management Plan, documentation of effective remote sensing EWM mapping methods, and an updated web-based EWM information clearinghouse helped guide landowners and managers within the Les Cheneaux watershed and across the Great Lakes basin on the appropriate use and limitations of the biocontrol and mechanical control (harvesting, tarping) techniques that have been implemented in the LCI. Results were disseminated with the help of the LCWC, who were collaborators for this proposed project.

Related Research

Arresting the Spread of Eurasian Watermilfoil (Myriophyllum spicatum) in the Great Lakes https://www.mtri.org/eurasian_watermilfoil.html

Smith et al. 2018: Use of Mycoleptodiscus terrestris as a mycoherbicide for Myriophyllum spicatum (Eurasian watermilfoil) management in the open-water system of the Les Cheneaux Islands, Michigan

Great Lakes Echo 2016 article: Fighting invaders with drones and fungi

For Additional Information

Colin Brooks

Amanda Grimm

Project Team

Colin Brooks - Principal Investigator
Dr. Amy Marcarelli - Co-Investigator
Dr. Casey Huckins - Co-Investigator
Amanda Grimm - Co-Investigator
Rick Dobson - Co-Investigator

Bob Smith - Collaborator, Les Cheneaux Watershed Council (LCWC)
Mark Clymer - Collaborator, Les Cheneaux Watershed Council (LCWC)