Eurasian Milfoil and how to control it.

Eurasian Milfoil

Why Kill Eurasian Milfoil?

Eurasian Milfoil if untreated will take over a lake in just a few seasons. Once established its dense mats of vegetation will change how your lake will function. Milfoil mats interfere with recreational activities such as swimming, fishing, water skiing, and boating. It can also effect power generation and irrigation by clogging water intakes. The sheer mass of plants can cause flooding and the stagnant mats can create good habitat for mosquitoes. Milfoil mats can rob oxygen from the water by preventing the wind from mixing the oxygenated surface waters to deeper water. Milfoil starts its spring growth sooner than native aquatic plants and can shade out these beneficial plants. When milfoil invades a new territory native weed diversity declines. While some species of waterfowl will eat milfoil, it is not considered to be a good food source. Eurasian Milfoil reproduces extremely fast and can infest an entire lake within two years of introduction to the system. Although milfoil produces many seeds, fragmentation is the main way this weed propagates. Late in the summer this weed naturally breaks apart and these parts (fragments) are able to float around and establish new colonies in other areas of the same body of water. Milfoil will also grow from fragments created by boaters or other disturbances during any time of year. A new plant can start from a tiny piece of a milfoil plant. This is why milfoil can so easily be transported from lake to lake on boat trailers or fishing gear

Best methods for the control of Eurasian Milfoil, if your community is against the use of chemicals and or your lake is tied to the well system or is used for drinking water then use the following control methods

  • Dredging - Remove the sediment to depths over 8 feet
  • Benthic barriers - Sunlight blocking barriers including dies, Plastic shading materials, and Lake Bottom Blanket
  • Mechanical devices - These massage the lake bottom in shallow water. Should be started before the plant starts to grow

IF your community is looking for a quick fix and doesn't care about the ecology and effects of the program instituted then you can follow the following methods:

  • Chemicals - Must contract a company to administer the chemical. Can change the O2 levels due to decaying biomass - Fish kills and algae issues due to not enough plant life in lake also increases the biomass load in the lake - producing Muck on bottom affects water use, depending on the chemical used. May need more than one application and also an application of an algaecide.
  • Mechanical harvesting - for removal of weeds that are canopied on top of the water. High cost and a continual project and can cause increase in the propagation due to fragmentation issues - need to make sure you removed all the weeds fragments otherwise it will spread to new location quickly. This also creates a more dense mat on re-growth. What to do with the removed biomass?
  • Hand Harvesting, Hand cutting , Rakes - Fragmentation issues - need to make sure you removed all the weeds fragments otherwise it will spread to new location quickly a continual project.