Abstract
Curlyleaf pondweed (Potamogeton crispus L.) is an invasive aquatic plant present across the United States that causes significant recreational issues, outcompetes native plant species, and depletes water quality. Before senescing in mid-summer, curlyleaf pondweed forms a large number of turions that can lay dormant in the sediment for several years. Typical herbicide management of this species occurs in early spring to target the plant before turion production occurs and while native plants are dormant. Flumioxazin has shown potential in curlyleaf pondweed management in small scale studies, but its effects have not been assessed in operational management. In this study, treatments occurred at concentrations of 75, 100, 125, and 150 μg L-1 of flumioxazin in May of 2024 and 2025 in Minnesota lakes. The effect of the treatments on curlyleaf pondweed and native plant presence, as well as curlyleaf pondweed turion sediment densities, were assessed for both years. Point intercept surveys were conducted prior to treatments in May, three weeks after treatment, and six weeks after treatment during the 2024 and 2025 seasons. Additionally, turion sampling occurred monthly between May and October in both seasons. Curlyleaf pondweed presence significantly decreased following treatments at rates of 100-150 μg L-1 (alpha = 0.05), with reductions being site specific. The 75 μg L-1 concentration was not effective at reducing curlyleaf pondweed presence during the first year of treatment, with limited success in the second. Mean native species richness (species point-1) did not decrease in any of the treatment plots following herbicide applications, and few negative species specific effects were observed. No between year effects were observed for sediment turion densities, but the magnitude of increase in densities between May and July was much lower in the treated sites than the reference sites, with treated sites ranging from 43-139 turions per m2 at their peak in July and non-treated sites averaging 464 turions per m2 during that same time period. These results suggest that flumioxazin can effectively manage curlyleaf pondweed, with rates of 100-150 μg L-1 providing the best control while maintaining native species selectivity.
Advisor
Ryan Wersal
Committee Member
Bradley Sartain
Committee Member
Matthew Kaproth
Date of Degree
2026
Language
english
Document Type
Thesis
Degree
Master of Science (MS)
Program of Study
Biology
Department
Biological Sciences
College
Science, Engineering and Technology
Recommended Citation
Jensen, P. J. (2026). Rate response of curlyleaf pondweed and native plants to flumioxazin in Minnesota lakes [Master’s thesis, Minnesota State University, Mankato]. Cornerstone: A Collection of Scholarly and Creative Works for Minnesota State University, Mankato. https://cornerstone.lib.mnsu.edu/etds/1610/
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Included in
Aquaculture and Fisheries Commons, Plant Sciences Commons, Water Resource Management Commons
Rights Statement
