Two Invasive Plant Projects Launched
Curlyleaf pondweed and Eurasian watermilfoil are major pests in Minnesota, occurring in over 750 and 280 water bodies respectively, disrupting recreation, and suppressing native species. While some methods to control these plants are already available, cost- effective and environmentally-sound options are needed. That’s where Dr. Ray Newman’s work comes into play. Starting this fall, Dr. Newman and his team are investigating biological control of Eurasian watermilfoil by a small native insect called the milfoil weevil. This weevil has been shown to reduce Eurasian watermilfoil in some lakes; however, something appears to be limiting its effectiveness in others. Dr. Newman suspects that bluegills, which feed on the weevils, are the culprits. To test his hypothesis, Dr. Newman will use vinyl experimental enclosures (similar to those pictured) in test lakes to determine if altering the sunfish population densities and size structures can create a quality fishery while also enhancing the milfoil weevil’s ability to safely and affordably control Eurasian watermilfoil.
Dr. Newman will also be analyzing data collected over the last 10-15 years by the Minnesota DNR, the University, watershed districts, and others on the response of curlyleaf pondweed—and native plants—to management. Gathering and analyzing this data will answer several questions: 1) how many subsequent herbicide treatments are needed for effective control 2) what time of year and/or how broadly applied should the treatments be to produce the best results and 3) how do native plants respond to curly leaf herbicide treatments? Dr. Newman hopes to have results to share by December, 2016.