Action: Floating pennywort: Combination treatment using herbicides and physical removal
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- A before-and-after study in Western Australia found that a combination of cutting followed by glyphosate chemical treatment, removed floating pennywort.
Removing the majority of floating pennywort Hydrocotyle ranunculoides biomass prior to targeted herbicide application offers a tool for localised population reduction, and can be used to prevent significant deoxygenation of the water body due to decomposition of treated plant material.
Supporting evidence from individual studies
A before-and-after study from 1993 to 1994 in a river in Western Australia (Ruiz-Avila & Klemm 1996) found that a combination of cutting followed by glyphosate chemical treatment, removed approximately 2,000 tonnes of floating pennywort Hydrocotyle ranunculoides. Floating pennywort mats were cut with sickles from small boats. The boats pushed mats to a conveyor harvester and mats were then floated to the bank, where they were removed. After most of the weed had been removed, the chemical glyphosate (Tradename Roundup) was applied along the banks at a rate of 360 g/ha of active ingredient in 1993 and 450 g/ha in 1994. The amount of floating pennywort removed was estimated from the number of truckloads. The area was monitored to assess re-infestation of floating pennywort and assess water quality. No further details were available.