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Providing evidence to improve practice

Action: Floating pennywort: Combination treatment using herbicides and physical removal Control of Freshwater Invasive Species

Key messages

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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.

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.


Referenced papers

Please cite as:

Aldridge, D., Ockendon, N., Rocha, R., Smith, R.K. & Sutherland, W.J. (2019) Some aspects of control of freshwater invasive species. Pages 569-602 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2019. Open Book Publishers, Cambridge, UK.