Methods of Eradication
Mechanical Control
Diver Assisted Suction Harvesting (DASH)
During DASH divers swim along the lake bottom to hand harvest target plant species. A key difference between DASH and more traditional hand harvesting methods is that divers don’t have to come to the surface as often to dispose of harvested plants. Instead, divers carefully feed the aquatic vegetation into the intake of a submerged suction hose that transports water and the plant material to the surface and into a boat’s bagging station. This means divers spend less time at the water’s surface and more time at the bottom, harvesting plants.
Hand raking
Eurasian watermilfoil can be removed by raking or seining it from the pond but will reestablish from any remaining fragments and roots.
Benthic barriers (bottom cover barriers)
Physical barriers are also used to eliminate plants by shading the bottom. These work well for swimming areas, docks, etc. but must be kept clean of any buildup of sediment and debris.
Chemical Control – Herbicides
One danger with any chemical control method is the chance of an oxygen depletion after the treatment caused by the decomposition of the dead plant material. Oxygen depletions can kill fish in the pond. If the pond is heavily infested with weeds it may be possible (depending on the herbicide chosen) to treat the pond in sections and let each section decompose for about two weeks before treating another section. Aeration, particularly at night, for several days after treatment may help control the oxygen depletion.
Natural predators