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  • Senecio jacobaea line drawing (Image: USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. Vol. 3: 542)
  • Senecio jacobaea (Photo: Jacobskruiskruid bloeiende plant, Wikimedia)
  • Senecio jacobaea (Photo: Richard Old, XID Services, Inc., Bugwood.org)
  • Senecio jacobaea seed heads (Photo: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org)
  • Senecio jacobaea seedlings (Photo: Utah State University Archive, Utah State University, Bugwood.org)
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Common name
Synonym
Jacobaea vulgaris , Gaertn
Similar species
Senecio aquaticus, Tanacetum vulgare, Senecio sylvaticus
Summary
Senecio jacobaea is a highly invasive, noxious weed which is known to invade pastoral land. It has detrimental impacts on livestock, due its highly toxic alkaloid content.
Species Description
Senecio jacobaea is categorised as a biennial plant. However, several studies have found it to demonstrate annual and perennial properties depending on environmental factors (Wardle, 1987). In the first year of its biennial stage, S. jacobaea is in the rosette stage. It has dark green, basal leaves which are typically 5-20cm in length and 4-6cm in width with whitish, slightly hairy underside. The blunt toothed lobes of the leaves contribute to the ruffled appearance of the rosette. Seeds of outer (ray) florets are hairless and are normally 2mm long, while those from the inner (disc) florets have fine bristles up to 5mm in length. In the second year, flowering takes place with one or several stems, growing up to 1.2m. Leaves on the flowering stems are sessile, occurring in an alternating pattern. The flower head itself has a daisy-like appearance, consisting of disc florets as well as ray florets and is usually 2.5cm across in diameter. One of the more notable characteristics of the ray flowers is its 11-15 yellow petals, each being 5 – 10mm long. S. jacobaea has a fibrous taproot and is typically associated with a large rootstock (NWCB, 2008).
Lifecycle Stages
The production of the seed is typically followed by the death of the individual plant (Sharrow , 1988). The majority of the seeds germinate in autumn, though delayed germination in spring can occur (Harper and Wood, 1957). Under favourable conditions, ragwort seeds are capable of a lengthy dormancy period of up to 8 years. Even after this period, the seed viability remains considerably high, especially when it is buried at lower depths (Wardle, 1987). It is likely that S. jacobaea utilises at least two distinct strategies for germination. This follows from the fact that disc achenes demonstrated greater dispersal in space than ray achenes. In addition, the disc achenes were more successful in germination compared to ray achenes under the same conditions (Warlde, 1987).
Uses
The juice of the plant is cool and astringent and is traditionally used as a wash for burns, sores, cancerous ulcers and eye inflammations (Grieve, 1987). Additionally, green and yellow dyes can be made from the leaves and the flowers of the plant respectively.
Habitat Description
Senecio jacobaea invades disturbed sites including roadsides, pastures and forest clearings (Macdonal & Russo, 1989). Records show that the distribution of the species is unlikely to be affected by extreme weather, although some cases have noted that a decrease in its population may be correlated with dry summers (Harper and Wood, 1957). Additionally, S. jacobaea distribution may be influenced by soil moisture, but not by soil acidity or texture (Sharrow et al, 1988).
Reproduction
Senecio jacobaea is known to be highly variable with regards to its reproductivity. For example, one study in Ruakura, New Zealand, showed that plants produced 1,000 to 2,500 capitula per season, with each capitulum containing 55 seeds. Whereas in the United Kingdom, S. jacobaea produced between 68 to 2,489 capitula per year and 70 seeds per capitulum (Wardle, 1987). Additionally, S. jacobaea is capable of reproducing vegetatively. The underlying mechanism is thought to be by basal branching, whereby the root connection with the parent plant decays, allowing each stem to form a new plant (Wardle, 1987).
Nutrition
Research indicates that Senecio jacobaea seeds requires light for germination, while maximum germination (92.5%) occurs during 15°C and 29% soil moisture content (Wardle, 1987).

Principal source:

Compiler: IUCN/SSC Invasive Species Specialist Group (ISSG) with support from ASB Community Trust, New Zealand
Updates with support from the Overseas Territories Environmental Programme (OTEP) project XOT603, a joint project with the Cayman Islands Government - Department of Environment

Review:

Publication date: 2010-10-04

Recommended citation: Global Invasive Species Database (2017) Species profile: Senecio jacobaea. Downloaded from http://www.iucngisd.org/gisd/species.php?sc=1348 on 18-12-2017.

General Impacts
In most introduced regions, Senecio jacobaea is considered to be an agricultural pest. It contains a highly potent pyrrolizidine alkaloid which is severely toxic to livestock, especially cattle and horses and to a lesser extent, sheep (Wardle, 1987). Also, S. jacobaea is known to invade disturbed native forests and woodlands, where it threatens biodiversity (DPI, 2007). Its high mortality rate after flowering leaves open bare patches on the pasture, allowing invasion of other noxious weeds which may further disrupt the ecological balance (DPIW, 2008).
Management Info
Management of Senecio jacobaea is tackled via an integrated approach, whereby a number of different preventative and control measures are used in conjunction with one another.

The Ragwort Control Guide outlines all the Do’s and Don’ts of ragwort control, including all the control and management options. The Herbicides for Ragwort control page lists all the herbicides that can be used for ragwort control, including application methods and concentrations.

Preventative measures: A wide range of preventative measures can be utilised to control further spread of ragwort. For example, ensuring that seed for planting is not contaminated with the seeds of S. jacobaea; using thoroughly cleaned vehicles, machinery and equipment; quarantine of heavily infested areas and careful disposal of plant seeds or flowers (DPI, 2007).

Physical: The most commonly adopted method is handpulling or grubbing, with the primary objective being preventing the plant from producing seed. Due to the plant’s regenerative properties, manual control must ensure that the entire crown and roots of the plants are removed. Cultivation of the soil should be carried out systematically to reduce regrowth. For example, the soil should be cultivated to a depth of at least 15cm in spring, with timed seasonal cropping programmes coupled with pasture improving regimes (DPI, 2007). Additionally, in Australia DPI (2007) suggests that afforestation with radiata pine or eucalyptus plantation can effectively suppress the spread of S. jacobaea via competition as well as acting as a windbreak and limiting seed dispersal (DPI, 2007).

Chemical: The best time for application is during the active growth phase of the plant, such that the pesticide is taken up by the crown and the root which is situated deep beneath the surface. A programme requires re-application and should primarily be targeted at the seedlings and rosettes during autumn and spring. It may be more effective to use herbicides that are selective for broadleaf weeds, so that other vegetation is left to compete with remaining ragwort. S. jacobaea can be chemically controlled via the use of 2,4-D and/or dicamba. In order for this method to be effective, the herbicides should be applied during certain developmental stages. For example, 2,4-D nets the best results when applied to seedlings and first year rosettes. A combination of 2,4-D and dicamba is shown to be successful just after the bolting phase (Macdonal & Russo, 1989).

Biological: Sheep appear to be less susceptible to the alkaloid toxicity and thus, heavy grazing can be an effective form of prevention, although it has been shown that even after extensive grazing, regrowth can rapidly occur after the removal of the stock. Thus animal grazing should be used as supplementary scheme only. In its native range, S. jacobaea has a number of natural predators, namely the cinnabar moth (Tyria jacobaeae), tansy ragwort seed fly (Pegohylemyia seneciella) and tansy ragwort flea beetle (Longitarsus jacobaea). The absence of these insects in the introduced range is thought to be directly responsible for its establishment in the respective regions. As a result, the introduction of these natural predators has shown to be an effective means of keeping the population of ragwort in balance (Macdonal & Russo, 1989).

Countries (or multi-country features) with distribution records for Senecio jacobaea
NATIVE RANGE
  • europe
  • western asia
Informations on Senecio jacobaea has been recorded for the following locations. Click on the name for additional informations.
Lorem Ipsum
Location Status Invasiveness Occurrence Source
Details of Senecio jacobaea in information
Status
Invasiveness
Arrival date
Occurrence
Source
Introduction
Species notes for this location
Location note
Management notes for this location
Impact
Mechanism:
Outcome:
Ecosystem services:
Impact information
In most introduced regions, Senecio jacobaea is considered to be an agricultural pest. It contains a highly potent pyrrolizidine alkaloid which is severely toxic to livestock, especially cattle and horses and to a lesser extent, sheep (Wardle, 1987). Also, S. jacobaea is known to invade disturbed native forests and woodlands, where it threatens biodiversity (DPI, 2007). Its high mortality rate after flowering leaves open bare patches on the pasture, allowing invasion of other noxious weeds which may further disrupt the ecological balance (DPIW, 2008).
Red List assessed species 0:
Management information
Management of Senecio jacobaea is tackled via an integrated approach, whereby a number of different preventative and control measures are used in conjunction with one another.

The Ragwort Control Guide outlines all the Do’s and Don’ts of ragwort control, including all the control and management options. The Herbicides for Ragwort control page lists all the herbicides that can be used for ragwort control, including application methods and concentrations.

Preventative measures: A wide range of preventative measures can be utilised to control further spread of ragwort. For example, ensuring that seed for planting is not contaminated with the seeds of S. jacobaea; using thoroughly cleaned vehicles, machinery and equipment; quarantine of heavily infested areas and careful disposal of plant seeds or flowers (DPI, 2007).

Physical: The most commonly adopted method is handpulling or grubbing, with the primary objective being preventing the plant from producing seed. Due to the plant’s regenerative properties, manual control must ensure that the entire crown and roots of the plants are removed. Cultivation of the soil should be carried out systematically to reduce regrowth. For example, the soil should be cultivated to a depth of at least 15cm in spring, with timed seasonal cropping programmes coupled with pasture improving regimes (DPI, 2007). Additionally, in Australia DPI (2007) suggests that afforestation with radiata pine or eucalyptus plantation can effectively suppress the spread of S. jacobaea via competition as well as acting as a windbreak and limiting seed dispersal (DPI, 2007).

Chemical: The best time for application is during the active growth phase of the plant, such that the pesticide is taken up by the crown and the root which is situated deep beneath the surface. A programme requires re-application and should primarily be targeted at the seedlings and rosettes during autumn and spring. It may be more effective to use herbicides that are selective for broadleaf weeds, so that other vegetation is left to compete with remaining ragwort. S. jacobaea can be chemically controlled via the use of 2,4-D and/or dicamba. In order for this method to be effective, the herbicides should be applied during certain developmental stages. For example, 2,4-D nets the best results when applied to seedlings and first year rosettes. A combination of 2,4-D and dicamba is shown to be successful just after the bolting phase (Macdonal & Russo, 1989).

Biological: Sheep appear to be less susceptible to the alkaloid toxicity and thus, heavy grazing can be an effective form of prevention, although it has been shown that even after extensive grazing, regrowth can rapidly occur after the removal of the stock. Thus animal grazing should be used as supplementary scheme only. In its native range, S. jacobaea has a number of natural predators, namely the cinnabar moth (Tyria jacobaeae), tansy ragwort seed fly (Pegohylemyia seneciella) and tansy ragwort flea beetle (Longitarsus jacobaea). The absence of these insects in the introduced range is thought to be directly responsible for its establishment in the respective regions. As a result, the introduction of these natural predators has shown to be an effective means of keeping the population of ragwort in balance (Macdonal & Russo, 1989).

Bibliography
25 references found for Senecio jacobaea

Managment information
Department of Primary Industries and Water (DPIW) 2008. Ragwort (Senecio jacobaea) Control Guide.
Summary: General and Management information Senecio jacobaea L. in Tasmania, Australia.
Available from: http://www.dpiw.tas.gov.au/inter.nsf/WebPages/RPIO-4ZZVLA?open [Accessed 26 March 2008]
Department of Primary Industries (DPI). 2007. Ragwort - Management.
Department of Primary Industries, Parks, Water and Environment, Tasmania, 2010. Ragwort Control Guide
Summary: Available from: http://www.dpipwe.tas.gov.au/inter.nsf/WebPages/LBUN-7ZLVRB?open [Accessed 26 July 2010]
Ireson, J. E., Leighton, S. M., Holloway, R. J., Chatterton, W. S., 2000. Establishment and redistribution of Longitarsus flavicornis (Stephens) (Coleoptera: Chrysomelidae) for the biological control of ragwort (Senecio jacobaea L.) in Tasmania. Australian Journal of Entomology. 39(1). Feb. 1, 2000. 42-46
Summary: A summary of the effectiveness of Longitarsus flavicornis in controlling the spread of ragwort in Tasmania, Australia.
IUCN/SSC Invasive Species Specialist Group (ISSG)., 2010. A Compilation of Information Sources for Conservation Managers.
Summary: This compilation of information sources can be sorted on keywords for example: Baits & Lures, Non Target Species, Eradication, Monitoring, Risk Assessment, Weeds, Herbicides etc. This compilation is at present in Excel format, this will be web-enabled as a searchable database shortly. This version of the database has been developed by the IUCN SSC ISSG as part of an Overseas Territories Environmental Programme funded project XOT603 in partnership with the Cayman Islands Government - Department of Environment. The compilation is a work under progress, the ISSG will manage, maintain and enhance the database with current and newly published information, reports, journal articles etc.
Macdonald, Cathy & Mary J. Russo, 1989. Element Stewardship Abstract for Senecio jacobaea (Tansy Ragwort, Tansy Butterweed)
Summary: Available from: http://www.imapinvasives.org/GIST/ESA/esapages/documnts/senejac.pdf [Accessed 26 July 2010]
McEvoy P, Cox C and Coombs E. 1991. Successful Biological Control of Ragwort, Senecio jacobaea, by Introduced Insects in Oregon. Ecological Applications, 1(4), 430-442
Summary: Biological control of ragwort in Oregon, USA.
McLaren D. A, Ireson J. E and Kwong R. M. 2000. Biological Control of Ragwort (Senecio jacobaea L.) in Australia. Proceedings of the X International Symposium on Biological Control of Weeds 4-14 July 1999, Montana State University, Bozeman, Montana, USA. Neal R. Spencer [ed.]. pp. 67-79.
Summary: An overview of the biological management of Senecio jacobaea L. in Australia.
Available from: http://www.invasive.org/publications/xsymposium/proceed/01pg67.pdf [Accessed 20 March 2010]
Pemberton R.W and Turner C.E. 1990. Biological control of Senecio jacobaea in northern California, an enduring success. Entomophaga, 35(1), 71-77.
Summary: Biological control of ragwort in northern California, USA.
Schmidl L. 1972. Biology And Control Of Ragwort, Senecio jacobaea L., In Victoria, Australia. Weed Research. 12,37-45.
Summary: Management information Senecio jacobaea L. in Victoria, Australia.
Taranaki Regional Council (TRC), undated. Ragwort and Pink Ragwort. Pest plant management
Summary: General and Management information Senecio jacobaea L. in Taranaki, New Zealand.
Available from: http://www.trc.govt.nz/environment/plants/pdf/ragwort14.pdf [Accessed 27 March 2008]
Varnham, K. 2006. Non-native species in UK Overseas Territories: a review. JNCC Report 372. Peterborough: United Kingdom.
Summary: This database compiles information on alien species from British Overseas Territories.
Available from: http://www.jncc.gov.uk/page-3660 [Accessed 10 November 2009]
General information
California Department of Food and Agriculture (CDFA), undated. Senecio Genus.
Summary: Management information Senecio jacobaea L. in California, USA.
Available from: http://www.cdfa.ca.gov/phpps/ipc/weedinfo/senecio.htm [Accessed 03 April 2008]
Environment Bay of Plenty (EBOP). 2005. Ragwort (Senecio jacobaea)
Summary: General and Management information Senecio jacobaea L. in Bay of Plenty, New Zealand.
Available from: http://www.envbop.govt.nz/land/media/pdf/Fact_Sheet_PP06.pdf [Accessed 27 March 2008]
Environment Waikato Regional Council (EW). undated. Ragwort, Plumeless Thistle and Nodding Thistle.
Grieve M. A., 1984. Modern Herbal. Penguin 1984 ISBN O-486-20459-6.
Summary: A background on the uses of Senecio jacobaea L.
Harper J.L and Wood W.A. 1957. Senecio jacobaea L. The Journal of Ecology. 45:(2); 617-637.
Summary: General ecology information about Senecio jacobaea L.
ITIS (Integrated Taxonomic Information System), 2008. Online Database Senecio jacobaea L.
Summary: An online database that provides taxonomic information, common names, synonyms and geographical jurisdiction of a species. In addition links are provided to retrieve biological records and collection information from the Global Biodiversity Information Facility (GBIF) Data Portal and bioscience articles from BioOne journals.
Available from: http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=36089 [Accessed 18 March 2008]
Ministry of Agriculture and Lands (MAL). Undated. Tansy ragwort in British Columbia.
Summary: Management information concerning Senecio jacobaea L. in British Columbia, Canada.
Available from: http://www.agf.gov.bc.ca/cropprot/tansy.htm [Accessed 03 April 2008]
Sharrow S.H, Ueckert D.N and Johnson A.E. 1988. Ecology and Toxicology of Senecio species with special reference to Senecio jacobaea and Senecio longilobus. The Ecology and Economic Impact of Poisonous Plants on Livestock Production. Boulder, CO. pp 181-197.
Summary: A summary of the ecology associated with Senecio jacobaea L.
The West Coast Regional Council (WCRC). Undated. Pest Plant: Ragwort
Summary: General and Management information Senecio jacobaea L. in West Coast, New Zealand.
Available from: http://www.wcrc.govt.nz/Resources/Documents/pestplants/PP%20Boundary%20-%20Ragwort.pdf [Accessed 27 March 2008]
USDA, ARS, 2008. Senecio jacobaea L. National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. National Germplasm Resources Laboratory, Beltsville, Maryland
Summary: General taxonomic information related to Senecio jacobaea L.
Available from: http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?104534 [Accessed 19 March 2008]
Wardle D. A. 1987. The ecology of ragwort Senecio jacobaea L. - A review. New Zealand Journal of Ecology, 10:67-76.
Summary: A summary of the ecology associated with Senecio jacobaea L.
Available from: http://www.newzealandecology.org/nzje/free_issues/NZJEcol10_67.pdf [Accessed 19 March 2008]
Washington State Noxious Weed Control Board. 2008. Information about tansy ragwort.
Summary: General information about Senecio jacobaea L. in the United States.
Available from: http://www.nwcb.wa.gov/weed_info/Senecio_jacobaea.html [Accessed 18 March 2008]
Contact
The following 0 contacts offer information an advice on Senecio jacobaea