
MAISRC research on Eurasian watermilfoil focuses on finding biological controls; integrating control with enhancement of native plants; and studying the distribution, ecology, and management of hybrid watermilfoil that arises from Eurasian watermilfoil crossing with the native species, northern watermilfoil. Click here to learn more about Eurasian watermilfoil and its impacts.
Key findings and accomplishments
- Found evidence of hybrid vigor and competitive advantage in hybrid watermilfoil, and sampled lakes around the state to genetically identify hybrid milfoil populations
- Developed and evaluated techniques to selectively control Eurasian and hybrid watermilfoil using native milfoil weevils
- Conducted enclosure and mesocosm experiments, as well as lake surveys, to assess the effect of sunfish predation on milfoil weevil densities and watermilfoil abundance to inform biocontrol strategies
- Determined that weevil populations are too low to control watermilfoil in many Minnesota lakes and that other factors, in addition to sunfish predation, are limiting populations
- Determined performance and fecundity of milfoil weevils on native, hybrid and Eurasian watermilfoil and in relation to host plant chemistry and quality
- Identified hotspots for Eurasian watermilfoil based on environmental variables and potential pathways of spread

Published papers
- Niche Models Differentiate Potential Impats of Two Aquatic Invasive Plant Species on Native Macrophytes
- Factors Influencing the Distribution of Invasive Hybrid (Myriophyllum Spicatum x M. Sibiricum) Watermilfoil and Parental Taxa in Minnesota
- A new device for sampling submersed aquatic plants using underwater video
- Effect of light on macrophyte sprouting and assessment of viable seedbank to predict community composition
- Association between submerged aquatic vegetation and elevated levels of Escherichia coli and potential bacterial pathogens in freshwater lakes
- Zebra mussels and Eurasian watermilfoil reporting patterns in Minnesota
- Environmental filtering and competitive exclusion drive biodiversity‐invasibility relationships in shallow lake plant communities
- Fecundity of a native herbivore on its native and exotic host plants and relationship to plant chemistry
- Assessment of factors affecting the biological control of Eurasian watermilfoil
- Chemically mediated host-plant selection by the milfoil weevil: A freshwater insect-plant interaction
- Fish predation on Eurasian watermilfoil (Myriophyllum spicatum) herbivores and indirect effects on macrophytes
- Chemical profile of the North American native Myriophyllum sibiricum compared to the invasive M. spicatum
- Biological control of eurasian watermilfoil by aquatic insects: Basic insights from an applied problem
- Distribution and abundance of the milfoil weevil, euhrychiopsis lecontei, in Lake Minnetonka and relation to milfoil harvesting
Completed projects
- Ecology and biology of invasive hybrid watermilfoil in northern tier waterbodies
- Metagenomic approaches to develop biological control strategies for aquatic invasive species
- Eco-epidemiological model to assess aquatic invasive species management
- Developing and evaluating new techniques to selectively control invasive plants
- Restoration and maintenance of native macrophytes in lakes – partnership with Riley Purgatory Bluff Creek Watershed
- Recognizing high-risk areas for zebra mussels and Eurasian watermilfoil invasions in Minnesota
Ongoing research
- Quantifying the genetic diversity of Eurasian, hybrid, and northern watermilfoil across the state to establish if the different genetic varieties present increased invasiveness or tolerance to current control techniques
- Investigating the ecology and invasiveness of hybrid watermilfoil, in comparison to native plant communities, to evaluate impacts and develop, prioritize, and refine management strategies
- Identifying pathogenic microbes associated with Eurasian watermilfoil and evaluating their specificity and effectiveness as biocontrol agents
- Studying the distribution, ecology, and management of hybrid watermilfoil
- Surveying lakes for abundance of milfoil weevils and other herbivores in relation to sunfish densities
- Examining sunfish diets to determine extent of predation by sunfish size
- Conducting mesocosm experiments with different densities of sunfish to experimentally determine the effects of sunfish on herbivores and milfoil control
Current projects
- Will property values cool as AIS heat up?
- Eurasian and hybrid watermilfoil genotype distribution in Minnesota
- Risk assessment, control, and restoration research on aquatic invasive plant species
- Managing for sustainable native macrophyte communities in lakes of the Riley-Purgatory Bluff Creek Watershed District
Additional information from MAISRC
- The latest on hybrid watermilfoil in Minnesota (Presentation)
- Assessing the response of Eurasian and hybrid watermilfoil to intensive herbicidal management in Minnesota (Poster)
- Restoring native plants after curlyleaf and milfoil control: What's holding them back? (Presentation)
- Will property values cool as AIS heat up? (Presentation)
- Hybrid watermilfoil map available
- Comparison of hybrid and parental watermilfoil growth and phenology in Minnesota (Presentation)
- New research challenges assumptions about biodiversity-invasibility relationships in lakes
- Hybrid watermilfoil in Minnesota: what is it, and where is it?
- Go underwater with MAISRC
- First hurdle cleared in search for microbial biocontrol agents against AIS
- Is hybrid watermilfoil the next resistant invader?
- Saving our lakes, one tiny weevil at a time
- New research to control Eurasian watermilfoil
- New suite of research on aquatic invasive plants kicks off
- Expanding research capacity for aquatic invasive plants
- U of M Adding Research Capacity in Aquatic Invasive Plants Management
- Two Invasive Plant Projects Launched