Eurasian watermilfoil management using newly developed technologies

Abstract

In British Columbia, Canada, managing Eurasian water-milfoil (Myriophyllum spicatum L.) integrates harvesting, tillage, bottom barrier applications, and diver-operated dredging methods in annual control programs in nine lakes. Two tillage technologies developed in British Columbia for removing plant roots in high use public areas are not known to have been applied in other jurisdictions. Barge-mounted rototillers achieve 80 to 97 percent reductions in stem densities in water depths up to 3.5 m. An amphibious cultivator is operated in water up to 1.25 m deep with similar effectiveness at lower unit cost and several times higher treatment rates. Both tillage machines may be operated in fall and spring and are particularly suitable during periods of lake drawdown. An independent researcher is developing applications of high power ultrasound to control Eurasian watermilfoil. Effects of laboratory experiments include damage to plant cells and tissues with single exposures of ultrasound for several seconds. This technology promises advantages for management and high levels of effectiveness in treatment of shoot and root tissues; current research is concentrated on reducing the exposure time required to kill meristematic tissues. © 1986 Taylor and Francis Group, LLC.