Aquatic Botony 76.3, 259-265 (2003).
Sallie P. Sheldon and Robert P. Creed, Jr. (2003) published findings in Aquatic Botany regarding the success that the biological control agent, Euhrychiopsis lecontei, had in decreasing biomass of the invasive Eurasian water milfoil (Myriophyllum spicatum). Native milfoils were exposed to varied numbers of weevils in a controlled laboratory setting. In vials containing more weevils, the milfoil had lower shoot lengths, highlighting a negative consequence when weevils were overly abundant. However, milfoils exposed to only one or two weevils did not have a significant plant biomass reduction. The experiment also showed that weevils did not hatch on native milfoils, suggesting that the reduced fecundity would leave native species at lower risk of harm. Sheldon and Creed (2003) concluded that E. lecontei are host-specific, and would be an appropriate control option for Eurasian water milfoil.
Wildlife activists and state officials are teaming up in the attempt to control and eliminate the noxious Eurasian water milfoil recently discovered in Montana. This invasive aquatic weed has continued to cause problems for local fisherman and boaters due to its’ characteristic behavior of forming a think layer of weeds on the surface of the water. As a result, sunlight can no longer permeate through the surface, and various wildlife species beneath the surface suffocate.
Efforts to control this problem include mandatory boat checks throughout the summer, frequent cleaning of boat bottoms and other fishing gear, and the spread of information regarding the effects of this non-native vegetation. According to the Wisconsin Department of Natural Resources website, the water milfoil thrives in bodies of water with a high concentration of nutrients. The author of the article continues to suggest that by integrating a watershed management program to keep nutrients out of the lakes, the milfoil colonies will be less likely to reproduce. Not only will these steps help control the problem, but manual labor consisting of physically extracting the plants out of the water and shore via rakes will also help. Another approach to eliminating the spread of the water milfoil is through mechanical cutters. On the downside, this method not only removes the unwanted milfoil canopy, but other native plants and vegetation, as well.
Various sites offered an assortment of methods for removing milfoil from bodies of water. I was relieved to find that one in particular listed a unique, alternative method of removal: biological control. Eurhychiopsis lecontei, an herbivorous weevil, is a known predator of the Eurasian water milfoil. Through this beetle’s reproductive processes, this invasive weed becomes extensively damaged. Even more, this North American native beetle prefers the Eurasian water milfoil to other native plants. As a result, fragile and native vegetation in the infested area would not be at risk during this method of treatment.
Clearly, there are more than enough ways to try and solve this epidemic. For this reason, I’m curious why this is still such an issue. The first appearance of the water milfoil in Wisconsin, for example, was in 1960. By 1993, the milfoil grew to take over 54% of the counties bays, lakes, and waterways. With the money, effort, and time being thwarted towards such a devastating weed, I would assume this problem would have been prevented in other areas. And yet, Belgrade News released an article on August 24th, 2010, announcing the invasion of this species in a Montana lake. Perhaps mere education and post-invasion clean ups are not sufficient to stop this spreading plant. The weed originated in Asia, Europe, and North America, and now appears in nearly multiple states. I suggest administering policies on the national level to prevent future spreading of this aquatic vegetation from state to state. By doing so, both the costs of restoration will be significantly minimized and overall ecosystems will be protected from this destructive, invasive, and overpowering specie.
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