Professor Sandra Cooke
24 March 2010
To Decline, or Not to Decline?
J. Aquat. Plant Manage 38: 105-111 (2000)
A study by Raymond M. Newman and David D. Biesboer (2000), both of the University of Minnesota, investigates whether there are possible relationships between the population of the milfoil weevil Euhrychiopsis lecontei and that of Eurasian watermilfoil (Myriophyllum spicatum). Control of the aquatic milfoil plant is important because it has harmed aquatic diversity, hindered human boating and recreation, and withstood both mechanical and chemical control methods. The researchers examined the Eurasian watermilfoil colonies and abiotic conditions, such as alkalinity, of the man-made Cenaiko Lake from 1996 to 1998. Samples of milfoil plants were collected from the lake and tested for carbohydrate analysis and weevil density determination after the plants were dried. The results of the study showed that declines in milfoil populations caused increases in the biomass of other plant species. Increases or decreases in weevil populations paralleled those in watermilfoil. The researchers conclude that larger-scale experiments involving the watermilfoil, weevil, and their environment will help support these findings.