Myriophyllum Spicatum - Control

Control

The aquatic moth Acentria ephemerella, the water veneer moth, feeds upon and damages this water milfoil. It has been used as an agent of biological pest control against the plant in North America. The milfoil weevil (Euhrychiopsis lecontei) has also been used as biocontrol. Another method for biocontrol is Grass Carp, (one of the Asian Carp species) which have been bred as sterility, is sometimes released into affected areas, since these fish primarily feed on aquatic plants and have proven effective at controlling the spread. However, the carp prefer many native species to the milfoil and will usually decimate preferred species before eating the milfoil. In Washington State the success rate of Grass Carp has been less than expected. They were used in 98 lakes and 39 percent of them had no submerged plant life left after only a short time.

Since roughly 2000, hand-harvesting of invasive milfoils has shown much success as a management technique. Several organizations in the New England states have undertaken large scale, lake-wide hand-harvesting management programs with extremely successful results. Acknowledgment had to be made that it is impossible to completely eradicate the species once it is established. As a result, maintenance must be done once an infestation has been reduced to afford-ably controlled levels. Well trained divers with proper techniques have been able to effectively control and then maintain many lakes, especially in the Adirondack Park in Northern New York where chemicals, mechanical harvesters, and other disruptive and largely unsuccessful management techniques are banned. After only three years of hand harvesting in Saranac Lake the program was able to reduce the amount harvested from over 18 tons to just 800 pounds per year.