Are currently recommended herbicides effective for control of ragwort (Senecio) species?
Published source details
Roberts P.D. & Pullin A.S. (2004) Are currently recommended herbicides effective for control of ragwort (Senecio) species? CEE (Collaboration for Environmental Evidence) Systematic Reviews, 5a, 04-003
Published source details Roberts P.D. & Pullin A.S. (2004) Are currently recommended herbicides effective for control of ragwort (Senecio) species? CEE (Collaboration for Environmental Evidence) Systematic Reviews, 5a, 04-003
Numerous ragworts Senecio spp. are poisonous to many mammals and can have lethal effects on grazing animals, particularly horses. In the UK, as a result of 'The Ragwort Control Act 2003', landowners have a duty to manage common ragwort S.jacobaea infestations so that they do not spread to adjacent land.
A systematic review (see: www.cebc.bham.ac.uk for methodology) was undertaken to evaluate the effectiveness of the herbicides available to control and those recommended for the control, of Senecio species. All quantitative studies and reports comparing a herbicide application (treatment plot) against no treatment (control plot) when looking at one or more of the following: common ragwort Senicio jacobaea; marsh ragwort S.aquaticus; Oxford ragwort S.squalidus or hoary ragwort S.erucifolius, were included within the review.
Meta-analyses showed that the herbicides: 2,4-D, Asulam, MCPA, Clopyralid, Triclopyr, Picloram, Flazasulfuron, Chlorsulfuron, Metasulfuron, 2,4-DB and the herbicide mixtures: 2,4-D/Dicamba and 2,4-D/Triclopyr are effective at increasing mortality of S.jacobaea compared to no treatment. However, not all herbicides are effective in reducing the population densities of ragwort species, even over a one year period. The current evidence from control trials suggests that either 2,4-D or MCPA will effectively increase mortality and reduce the population density of S.jacobaea (but not S. aquaticus) thus potentially providing effective control. Asulam and Clopyralid did not significantly reduce S.jacobaea density. However for reduction of S.aquaticus, Asulam application appears most effective, whilst 2,4-D and MCPA appeared not to significantly reduce its density.
The authors recommend further trials are required in three areas of herbicidal control of ragwort: 1) All herbicides with small sample numbers within this systematic review. 2) Species specific trials to determine which herbicide to use to control a particular Senecio species. 3) The method of herbicide application as data is currently lacking regarding application using spot spraying, rope wick and weed wiping.
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