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Providing evidence to improve practice

Individual study: Controlling New Zealand pygmyweed Crassula helmsii in field ditches and a gravel pit by herbicide spraying at Dungeness RSPB Reserve, Kent, England

Published source details

Gomes B. (2005) Controlling New Zealand pygmyweed Crassula helmsii in field ditches and a gravel pit by herbicide spraying at Dungeness RSPB Reserve, Kent, England. Conservation Evidence, 2, 62-62


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Crassula helmsii: Chemical control using herbicides Control of Freshwater Invasive Species

A before-and-after study in 2001-2004 at waterbodies in a nature reserve in Kent, UK (Gomes 2005) reported that application of either diquat-based herbicide or glyphosate killed most C. helmsii plants, although no statistical tests were carried out. Spraying once, using diquat on field ditches and glyphosate on the margin of a gravel pit, killed 70% of C. helmsii. A second application of diquat the following year was recorded as being ‘partially successful’ (no data given). However the authors reported that re-growth of C. helmsii was ‘noticed annually’ at sites treated with both chemicals. The diquat-based chemical Reglone was sprayed onto 50 m2 ditch at a rate of 10 l for 300 m in August-September 2001 and 2002. Glyphosate was applied at an unknown concentration in August-September 2004.