Saturday, May 26, 2018


What is Eurasian Watermilfoil? This summer has seen an overabundance of native weeds in Pentwater Lake, causing difficulties around docks and in swimming areas. Also our old enemy, Eurasian Water-milfoil, is making a strong comeback. Eurasian milfoil is an exotic aquatic plant that was accidentally introduced to North America from Europe and spread westward into inland lakes by boats and by water birds. It reached the midwestern states between the 1950s and 1980s. In nutrient-rich lakes it can form thick underwater stands of tangled stems and vast mats of vegetation at the water’s surface. In shallow areas it will interfere with boating, fishing and swimming. The plant’s floating canopy can also crowd out important native water plants. A key factor in its success is the plant’s ability to reproduce through stem fragmentation and underground runners. A single segment of stem and leaves can take root and form a new colony. The mechanical clearing of weed beds for beaches, docks and landings creates thousands of new stem fragments. Removing native vegetation creates perfect habitat for invading Eurasian watermilfoil. Because milfoil spreads by fragmentation, weed control procedures under the direction of Pentwater Lake Improvement Board each year provide for eradication of milfoil (by herbicides) before harvesting native weeds around docks, etc. Biological control is another tool that has been used. In 2001, native weevils that feed on milfoil were introduced into the Pentwater Marsh in hopes that they would foster decline of Eurasion milfoil in that area and gradually spread to the rest of the lake. Although some success has been noted in the marsh, the weevils have obviously not been able to multiply fast enough to hold down growth in the lake. - Editor

If you have any questions email us at

Leavitt & Associates Marketing L.L.C. 231.233.1520

Copyright 2018 by Pentwater Lake Association