Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Senecio madagascariensis



Senecio madagascariensis (fireweed)


  • Last modified
  • 21 November 2019
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Preferred Scientific Name
  • Senecio madagascariensis
  • Preferred Common Name
  • fireweed
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Dicotyledonae
  • Summary of Invasiveness
  • S. madagascariensis has spread rapidly in south-eastern Australia and Argentina following its accidental introduction from South Africa during the twentieth century. In the absence of rigorous phytosanitary controls, it is likely to spread further, e...

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Typical plant habit showing flowers at various stages and seed heads.
CaptionTypical plant habit showing flowers at various stages and seed heads.
Copyright©Sheldon Navie
Typical plant habit showing flowers at various stages and seed heads.
HabitTypical plant habit showing flowers at various stages and seed heads.©Sheldon Navie
Copyright©Sheldon Navie
SeedlingSeedling.©Sheldon Navie
Typical leaves.
CaptionTypical leaves.
Copyright©Sheldon Navie
Typical leaves.
LeavesTypical leaves.©Sheldon Navie
Close-up of flowers.
CaptionClose-up of flowers.
Copyright©Sheldon Navie
Close-up of flowers.
FlowersClose-up of flowers.©Sheldon Navie
Seed heads with some seeds already detached.
CaptionSeed heads with some seeds already detached.
Copyright©Sheldon Navie
Seed heads with some seeds already detached.
SeedsSeed heads with some seeds already detached.©Sheldon Navie


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Preferred Scientific Name

  • Senecio madagascariensis Poiret

Preferred Common Name

  • fireweed

Other Scientific Names

  • Senecio burchellii auct. non DC.
  • Senecio burchellii auct. non DC. sensu Cabrera
  • Senecio incognitus Cabrera
  • Senecio junodianus O. Hoffm.
  • Senecio ruderalis Harvey

International Common Names

  • Spanish: senecio amarillo (Argentina)

Local Common Names

  • Germany: Greiskraut, Burchells; Kreuzkraut, Burchells

EPPO code

  • SENBU (Senecio burchellii)
  • SENIN (Senecio incognitus)
  • SENMD (Senecio madagascariensis)

Summary of Invasiveness

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S. madagascariensis has spread rapidly in south-eastern Australia and Argentina following its accidental introduction from South Africa during the twentieth century. In the absence of rigorous phytosanitary controls, it is likely to spread further, especially where land is poorly managed and overgrazed. S. madagascariensis is undesirable because of its prolific achene production, vigorous growth and toxicity which can lead to the invasion of pastureland and the consequent toxic effects on livestock.

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Dicotyledonae
  •                     Order: Asterales
  •                         Family: Asteraceae
  •                             Genus: Senecio
  •                                 Species: Senecio madagascariensis

Notes on Taxonomy and Nomenclature

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Morphological variation within S. madagascariensis has led to a complex and confusing taxonomy for the species, particularly for the identity of the introduced taxon. This is due to the similarity between two disjunct groups of species, one in South Africa and Madagascar (S. madagascariensis Poiret complex; Hilliard, 1977) and the other in Australia (S. lautus Forster f. ex Willd. complex; Ali, 1969). In southern Africa, Hilliard (1977) placed S. ruderalis Harvey, S. junodianus O. Hoffm. and S. incognitus Cabrera, together with S. burchellii auct. non DC sensu Cabrera (Cabrera, 1963) into synonymy with S. madagascariensis. Furthermore, Hilliard (1977) placed the three varieties of S. madagascariensis recognized by Humbert (1963) into synonymy with S. madagascariensis (var. madagascariensis and var. boutoni (Baker) Humbert) and S. skirrhodon DC. (var. crassifolius Humbert). Hind et al. (1993) recognized S. madagascariensis var. boutoni at species level as S. boutonii Baker, and as endemic to the island of Rodrigues. Hilliard (1977) emphasized that S. madagascariensis is frequently confused with S. burchellii DC., S. pellucidus DC. and S. inaequidens DC. The two former taxa are separated from S. madagascariensis based on inflorescence shape, involucral bract and ray floret number, and distribution in southern Africa. However, the differentiation between S. madagascariensis and S. inaequidens is more difficult in the native range, since it is based on slight differences in stem woodiness, involucral bract length and the occurrence of S. inaequidens at elevations greater than 1500 m in Natal, South Africa. Hilliard (1977) agreed that the maritime species, S. skirrhodon may be no more than a maritime form of S. madagascariensis, as suggested by Humbert (1963).
The distinction between S. madagascariensis and S. inaequidens is controversial. Traditionally a distinction has been made between these two taxa, whilst recent evidence suggests that they are conspecific, differing only in ploidy level (Scott et al., 1998).

The epithet 'madagascariensis' refers to the Madagascan origin of the first collection made by Phillippe de Commerson.

The origin of the Australian common name 'fireweed' is unknown, although Sindel et al. (1998) suggest that this may be because of the species' ability to 'spread like wild-fire', its bright yellow colour, its supposed ability to cause spontaneous combustion in hay or its appearance after fire.


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Herbaceous, short-lived perennial, up to 60 cm tall, arising from a shallow taproot. Stems are erect, often much branched. Leaves alternate, bright green, occasionally petiolate, becoming reduced in size from the base, very variable, up to 12 cm long and 2.5 cm wide. Cauline leaves mostly linear-lanceolate to elliptic-lanceolate, apex acute, margins denticulate to coarsely and irregularly toothed, tapering to a narrow petiole-like amplexicaule base, sometimes auriculate. Upper leaves occasionally pinnately lobed, reduced petiolate, subsessile or sessile. S. madagascariensis has predominantly a2-type leaves of Ali's (1964) classification of S. lautus leaves. Leaves differ in the degree of dissection, width of the lobes and in the presence of hairs. Inflorescence an open, terminal or axillary, corymbose panicle. Capitula (7-)12-25 mm diameter, radiate, involucral bracts lanceolate (20-21), acute, ±glabrous, with membranaceous edge, 4-5(-6) mm long x 0.8-1.3 mm wide, keeled, resinous; calyculus bracts lanceolate (8-12), acute, ±glabrous, often purple tipped, 1-2 mm long. Ray florets 12-13, female, ligule bright yellow with resinous veins on upper surface, 8-14 mm long. Disc florets numerous, perfect, tube bright yellow. Achenes ca. 9- to 10-ribbed, 1.4-2.2 mm long x 0.3-0.45 mm diameter, pubescent between ribs. Pappus white, two- to three-times as long as achenes, readily detached.

Plant Type

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Seed propagated
Vegetatively propagated


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S. madagascariensis is considered native to southern Africa and Madagascar.

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Last updated: 17 Dec 2021
Continent/Country/Region Distribution Last Reported Origin First Reported Invasive Reference Notes


MadagascarPresent, WidespreadNative
MozambiquePresent, LocalizedNative
South AfricaPresent, WidespreadNative



North America

United StatesPresentPresent based on regional distribution.


AustraliaPresentPresent based on regional distribution.
-New South WalesPresent, WidespreadIntroducedInvasive
-QueenslandPresent, WidespreadIntroducedInvasive
-VictoriaPresent, LocalizedIntroducedInvasive

South America

ArgentinaPresent, LocalizedIntroducedInvasiveFirst reported: 1940s
-Rio Grande do SulPresent
ColombiaPresent, LocalizedIntroduced

History of Introduction and Spread

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S. madagascariensis may have been introduced to Australia in ship ballast from the South African Cape (Sindel, 1996). The earliest recorded specimen from New South Wales was collected in 1918 (Sindel et al., 1998), and was introduced north in crop seed in 1940 (Green, 1953). The species has recently spread to the south coast of New South Wales and to south-eastern Queensland (Sindel et al., 1998; Sindel and Michael, 1992a; Radford et al., 1995a).

S. madagascariensis was first recorded from Argentina in the early 1940s from the Port of Bahia Blanca (as S. incognitus; Cabrera, 1941), and is now found in the provinces of Buenos Aires, Santa Fe, Rios, Corrientes and Mendoza (Verona et al., 1982; Volkart, 1984; Tracanna and Catullo, 1987). S. madagascariensis has also been recorded as introduced into the highlands of Kenya (2600 m; Medley, 1997) and Colombia (2800 m; Sindel et al., 1998).

Risk of Introduction

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Further spread is highly probable, owing to the risks of accidental movement and contamination of agricultural produce.


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In its native southern Africa range, S. madagascariensis is found in disturbed areas. It is opportunistic with the ability to colonize a wide range of habitats, and will grow on a wide range of substrates (Verona et al., 1982) but prefers well-drained, fertile, disturbed soils. However, it will grow in low fertility soils in the absence of competition (Watson et al., 1994).

Habitat List

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Terrestrial ManagedCultivated / agricultural land Present, no further details
Terrestrial ManagedManaged forests, plantations and orchards Present, no further details
Terrestrial ManagedManaged grasslands (grazing systems) Present, no further details Harmful (pest or invasive)
Terrestrial ManagedDisturbed areas Present, no further details
Terrestrial ManagedRail / roadsides Present, no further details
Terrestrial ManagedUrban / peri-urban areas Present, no further details

Hosts/Species Affected

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S. madagascariensis is not normally a weed of crops but is a major concern wherever poorly managed and overgrazed pasture occurs (Sindel et al., 1998).

Biology and Ecology

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A chromosome number of 2n=(2x)=20 has commonly been reported for Australian and Argentinian S. madagascariensis (Verona et al., 1982; Radford et al., 1995b), although Hunziker et al. (1989) have reported a chromosome number of n=20 from Argentinian S. madagascariensis. Examples for putative hybrids between S. madagascariensis and S. lautus have been recorded in Queensland, Australia (McFadyen and Sparks, 1996). Artificial crosses between these two species are sterile (Sindel et al., 1998). Hybrids in the native range are not reported. However, the taxonomic confusion that exists with S. madagascariensis means that detection of natural hybridization will be difficult. Investigations of neutral genetic markers has been limited. Sindel et al. (1998) report low levels of alloenzyme variation in Australian S. madagascariensis, whilst Scott et al. (1998) report no variation in the internal transcribed spacer 1 (ITS1) of the nuclear ribosomal DNA sequence from Australian and Madagascan S. madagascariensis. In both of these studies, the main genetic variation was between South African/Australian and Madagascan populations.

To understand the genetics, systematics and morphological variation of S. madagascariensis, it is necessary to investigate populations from the exotic ranges of S. inaequidens and S. madagascariensis in more detail, together with material from southern Africa of S. madagascariensis, S. inaequidens, S. burchellii, S. pellucidus, S. skirrhodon and S. harveianus.

Physiology and Phenology

S. madagascariensis contains pyrrolizidine alkaloids (PA), some of which are highly toxic to animals and humans (Mattocks, 1986). The PA senecionine has been reported from S. madagascariensis (as S. lautus; Rizk, 1991; Mattocks, 1986). PAs are not toxic to mammals per se, rather the hazard arises through the normal oxidative detoxification mechanisms in the liver that convert them to pyrrolic metabolites (dehydroalkaloids; Mattocks, 1986). Hepatotoxicity or carcinogenicity of these highly reactive electrophilic alkylating agents is a result of their binding to nucleophilic centres in tissues or to cross-link DNA (Mattocks, 1986; Woo et al., 1993; Stegelmeier et al., 1999; Kim et al., 1999; Fu et al., 2001).

In S. jacobaea, there is considerable variation in the total PA concentration and concentration of individual PAs from plant-to-plant (Witte et al., 1992). Hartmann and Zimmer (1986) found that the highest PA content occurred in the capitula, and that PA concentration was five- to ten-fold higher than in the roots and leaves.

Reproductive Biology

S. madagascariensis is a short-lived perennial (Green, 1953; Cabrera and Ré, 1965; Martin and Colman, 1977; Verona et al., 1982) but it commonly behaves as an annual (Hilliard, 1977; Walker and Kirkland, 1981); it has also been recorded as a biennial (Humbert, 1963).

Capitula open when expanding disc florets force the involucral bracts apart. Expansion and unrolling of ray florets occurs in less than 24 h; stigmas are receptive as soon as the floret is expanded. Disc florets open later (centripetally). The capitula are visited by many types of insect, mainly Hymenoptera and Diptera (Sindel et al., 1998). Sindel et al. (1998) indicate that S. madagascariensis is self-incompatible; probably with sporophytic self-incompatibility, in common with other members of the Asteraceae (Hiscock, 2000). Thus, S. madagascariensis is another example of a successful self-incompatible colonizer in the genus like S. squalidus (Brennan et al., 2002) and S. jacobaea.

Propagation is primarily by achenes, although vegetative propagation by roots may also occur (Sindel et al., 1998). Individual S. madagascariensis plants vary greatly in the number of achenes they produce (Fernandez and Verona, 1984; Sindel and Michael, 1996; Sindel et al., 1998). Three types of achenes are produced (dark brown, light brown and green); the dark brown and green achenes appear to be associated with the ray florets (Sindel et al., 1998). These achenes do not differ in mean weight or length (Alonso et al., 1982) but they do have different germination rates and dormancies. Putative disc floret achenes germinate more quickly than ray floret achenes (Sindel et al., 1998), as has been found for S. jacobaea (McEvoy and Cox, 1987). Extreme temperatures induce achene dormancy, although under normal conditions dormancy is negligible (Alonso et al., 1982). Light and nitrates will stimulate achene germination but they are not essential (Alonso et al., 1982). However, Guillen et al. (1984) indicate that S. madagascariensis achenes are positively photoblastic.

Information on achene longevity is conflicting. Achenes may remain viable for up to 5 years when stored dry (Alonso et al., 1982). However, by extrapolation from experiments on achenes buried 3 cm below the soil surface for 15 months, Sindel et al. (1998) indicate that achenes will remain viable for more than 10 years.

Vegetative reproduction can occur from root fragments and intact roots and rooting along decumbent stems (Sindel et al., 1998).

Environmental Requirements

S. madagascariensis is opportunistic with the ability to colonize a wide range of habitats. It occurs on the eastern seaboard of the three southern Hemisphere continents at similar latitudes and is most successful in humid maritime and sub-tropical climates; it tends to be restricted to climates with low frost incidence (Sindel and Michael, 1989).

Air Temperature

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Parameter Lower limit Upper limit
Mean annual temperature (ºC) 10 20


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ParameterLower limitUpper limitDescription
Mean annual rainfall5001500mm; lower/upper limits

Rainfall Regime

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Soil Tolerances

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Soil drainage

  • free

Soil reaction

  • alkaline
  • neutral

Soil texture

  • light
  • medium

Special soil tolerances

  • infertile

Natural enemies

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Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Puccinia lagenophorae Pathogen

Notes on Natural Enemies

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Holtkamp and Hosking (1996) summarize more than 100 insect species that have been found on S. madagascariensis in Australia. These are primarily Coleoptera, Hemiptera and Lepidoptera. In Argentina, ants also attack S. madagascariensis (Verona et al., 1982). Three fungi have been recorded from S. madagascariensis (Wilson et al., 1965; Fernandez and Montes, 1987; Delhey and Kiehr, 1988; Holtkamp and Hosking, 1993), of which the most important is Puccinia lagenophorae.

Means of Movement and Dispersal

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Natural Dispersal (Non-Biotic)

Achenes are wind-dispersed. Disturbance is a major factor in the establishment of S. madagascariensis and populations are limited more by the availability of microsites for germination and establishment than by achene availability.

Vector Transmission (Biotic)

Humans and their animals transport achenes (Sindel et al., 1998).

Agricultural Practices

The movement of hay is likely to spread achenes (Sindel et al., 1998). The movement of livestock, and survival of achenes in faeces, is also likely to aid dispersal. Poor management of pasture provides ideal conditions for the establishment of S. madagascariensis.

Accidental Introduction

S. madagascariensis may be accidentally introduced by man, as a result of movement of soil during building works, and by attachment to vehicles or in the slip-stream of road vehicles.

Pathway Vectors

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VectorNotesLong DistanceLocalReferences
Containers and packaging - woodHay packaging Yes
Land vehiclesFarm vehicle, etc Yes
Plants or parts of plantsLivestock feed Yes

Plant Trade

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Plant parts liable to carry the pest in trade/transportPest stagesBorne internallyBorne externallyVisibility of pest or symptoms
Flowers/Inflorescences/Cones/Calyx weeds/fruits
Fruits (inc. pods) weeds/fruits
Growing medium accompanying plants weeds/fruits
Leaves weeds/fruits
Stems (above ground)/Shoots/Trunks/Branches weeds/fruits
Plant parts not known to carry the pest in trade/transport
Seedlings/Micropropagated plants
True seeds (inc. grain)

Impact Summary

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Animal/plant collections None
Animal/plant products None
Biodiversity (generally) None
Crop production None
Environment (generally) Negative
Fisheries / aquaculture None
Forestry production None
Human health None
Livestock production Negative
Native fauna None
Native flora None
Rare/protected species None
Tourism None
Trade/international relations Negative
Transport/travel None


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The primary economic impact of S. madagascariensis is through the reduction in pasture productivity, though competition with useful species and toxicity to livestock (Seaman and Walker, 1985; Small et al., 1993; Sindel et al., 1998) are also important. It has the reputation of being the worst weed in the coastal areas of New South Wales, Australia (Sindel and Michael, 1988). In Australia, pyrrolizidine alkaloid (PA) toxicosis is a general cause of heavy livestock losses (Culvenor, 1985). Livestock generally avoid S. madagascariensis because of the toxic PAs, although it will be eaten when present in hay. Peterson and Culvenor (1983) have reviewed syndromes of PA poisoning in domesticated animals. Acute poisoning (and death) occurs from a large intake of the plant over a short period. However, chronic poisoning over a longer period is more usual, and results from sublethal poisoning over weeks or years (Bull et al., 1968; McLean, 1970; Mattocks, 1986). S. madagascariensis is primarily hepatotoxic (Harding et al., 1964; Bull et al., 1968). Livestock and equines differ widely in their sensitivity to PAs (Anon., 1988): sheep and goats are resistant, cattle and horses less so, and poultry and pigs rather sensitive (Hooper, 1978). The resistance of sheep to PA poisoning has been ascribed to the destruction of the alkaloids in the rumen by conversion into non-toxic 1-methylenepyrrolizidine derivatives (Bull et al., 1968; Craig et al., 1986).

Environmental Impact

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S. madagascariensis competes with natural vegetation, reducing grass and other low-growing plants (Sindel et al., 1998; Radford and Cousens, 2000). This can lead to soil erosion as well as a loss in biodiversity.

Impact: Biodiversity

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No direct impacts of S. madagascariensis on biodiversity have been found.

Social Impact

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The aetiology of pyrrolizidine alkaloid (PA) poisoning in humans was first described by Wilmont and Robertson (1920; wheat flour contaminated with leaves and achenes of Senecio ilicifolius and S. burchellii). Human disease caused by PA toxicity is endemic to Central Asia (Anon., 1988) and PA poisoning from S. vulgaris achenes was reported in 1994 in a group of Bedouins in northern Iraq (Altaee and Mahmood, 1998). There appear to be no cases of human death caused by the PAs derived from consumption of S. madagascariensis.

PAs and/or toxic metabolites are secreted in the milk of lactating dairy cattle (Dickinson and King, 1978; Goeger et al., 1979; Deinzer et al., 1982; Geoger et al., 1982b; Molyneux and James, 1990) and have been found in eggs (Edgar and Smith, 1999). However, because commercial milk supplies are bulked there is unlikely to be significant human exposure by this route (Australia New Zealand Food Authority, 2001). S. madagascariensis may be a honey plant in parts of south-eastern Australia (Sindel et al., 1998); however, the consequences of low-level PA exposure for human health are unclear (Australia New Zealand Food Authority, 2001).

Risk and Impact Factors

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  • Proved invasive outside its native range
  • Highly adaptable to different environments
  • Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
  • Highly mobile locally
  • Has high reproductive potential
  • Has propagules that can remain viable for more than one year
Impact outcomes
  • Negatively impacts agriculture
  • Negatively impacts human health
  • Negatively impacts animal health
  • Negatively impacts tourism
  • Reduced amenity values
Impact mechanisms
  • Competition - monopolizing resources
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally
  • Difficult to identify/detect as a commodity contaminant
  • Difficult to identify/detect in the field
  • Difficult/costly to control


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S. madagascariensis may be an important food plant for wild insect species in its native range and for honey production in Australia (Sindel et al., 1998).

Similarities to Other Species/Conditions

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S. madagascariensis is most readily confused with members of the Australian species complex S. lautus. However, as indicated in Notes on Taxonomy and Nomenclature there is still doubt over the absolute distinction between S. madagascariensis and S. inaequidens. On the basis of limited sampling, Radford et al. (2000) indicate that S. madagascariensis can be distinguished from S. inaequidens by its smaller achenes (1.5-2.0 mm long versus 2.6 mm), with hairs confined to the achene grooves, in contrast to the completely hairy achenes of S. inaequidens. In the absence of more detailed comparative morphological examination, these differences must be treated with caution. S. madagascariensis is a diploid (2n=2x=20; Sindel et al., 1998), whilst S. inaequidens is a tetraploid (2n=4x=40; Radford et al., 2000). Sindel et al. (1998) discuss at length the separation of S. madagascariensis from the native Australian species S. lautus. This is based on achene length, involucral bract number and chromosome number.

Prevention and Control

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Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Cultural Control

The most important principle of any S. madagascariensis control programme is the maintenance of vigorous pasture species (Launders, 1986; Sindel and Michael, 1988). Low stocking rates or no grazing at peak emergence times can provide some control (Sindel et al., 1998). Sheep will graze S. madagascariensis (Watson et al., 1994) and show a high tolerance of pyrrolizidine alkaloids (PAs), particularly older sheep (Brenchley, 1920; Sharrow and Mosher, 1982; Amor et al., 1983; Olson and Lacey, 1994; Betteridge et al., 2000). However, continuous exposure of sheep to PAs should be avoided because toxicity problems can occur. Following grazing, S. madagascariensis plants may recover quickly and produce new shoots. A second crop of flowers may be produced following grazing at the flowering stage, which will necessitate a further grazing if achene production is to be prevented. Sheep-based control of S. madagascariensis cannot be recommended on animal welfare grounds.

Mechanical Control

Mechanical approaches to S. madagascariensis control include cutting, digging-out, hand-pulling and machine-pulling; each of these treatments may need to be repeated two or three times per year (preferably before flowering). Cutting is a useful emergency treatment to prevent fruiting, although the plants must be cut before the achenes are mature and the treatment must be followed by another control treatment because cutting may encourage the production of side shoots. Digging-out and hand-pulling (using gloves) are not practical for large areas of S. madagascariensis infestation. A problem of both digging-out and hand-pulling methods are that small plants may be missed, hence the need for annual treatment. Machine-pulling is suitable for large areas of infestation, and plants are selected on the basis of height differences. There is evidence that mowing may promote regrowth (Verona et al., 1982).

Chemical Control

Different types of herbicide, application methods and times of application have been tested in Australia for the control of S. madagascariensis (Anderson and Panetta, 1995).

Bromoxynil is effective on young plants, although a higher rate was needed after bud formation (Sindel et al., 1998). In Argentinian trials, glyphosate was as effective at bromoxynil but was followed by re-infestation (Tracanna et al., 1983). Top dressing pastures with nitrogen fertilizer after herbicide treatment may inhibit futher S. madagascariensis growth due to the rapid growth of competitors (Sindel and Michael, 1992b; Allan et al., 2001). Generally, multirope, carpet wipers or rotary wipers are more effective than simple rope wick applicators (Allan et al., 2001). The optimum time for herbicide application is at the seedling or early flowering stage (Tracanna et al., 1983). Since S. madagascariensis germination occurs in flushes throughout the season, a single herbicide application is unlikely to be effective.

To be most effective herbicide control should be undertaken in conjunction with pasture management.

Biological Control

Pests associated with S. madagascariensis in Australia do not discriminate between it and the native species S. lautus (Holtkamp and Hosking, 1993). Thus biological control programmes have been of limited success. In addition, the search for insect pests has focused on Madagascar (Marohasy, 1989), whilst DNA and alloenzyme data suggest that Australian S. madagascariensis is more closely related to South African populations (Scott et al., 1998; Radford et al., 2000). More success may be achieved by searching for potential biological control agents in South Africa (Radford et al., 1995a; McFadyen and Sparks, 1996).

Integrated Control

Integrated management involves containment, reduction and finally elimination of S. madagascariensis. Such long-term control has a short-term goal of preventing achene production in infested areas, and is emphasized by all control recommendations. In general, S. madagascariensis occurrence in pastures is a symptom of poor management, therefore re-seeding and grazing and fertility management may be essential components of a control plan.


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Ali SI, 1964. Senecio lautus complex in Australia. II. Cultural studies of populations. Australian Journal of Botany, 12:292-316

Ali SI, 1969. Senecio lautus complex in Australia. V. Taxonomic interpretations. Australian Journal of Botany, 17:161-176

Allan H, Launders T, Walker K, 2001. Fireweed. AGFACTS - NSW Agriculture, No. P7.6.26 (third Edition):12 pp

Alonso S, Fernadez O, Langero S, Verona C, 1982. Characteristics of seed germination of Senecio madagascariensis Poiret (Compositae). Ecologia, 7:95-116

Altaee MY, Mahmood MH, 1998. An outbreak of veno-occlusive disease of the liver in northern Iraq. Eastern Mediterranean Health Journal, 4(1):142-148; 17 ref

Amor RL, Lane DW, Jackson KW, 1983. Observations on the influence of grazing by sheep or cattle on the density and cover of ragwort. Australian Weeds, 2(3):94-95

Anderson TMD, Panetta FD, 1995. Fireweed response to boomspray applications of different herbicides and adjuvants. Plant Protection Quarterly, 10:152-153

Anon., 1988. Pyrrolizidine alkaloids. Environmental Health Criteria 80. Geneva, Switzerland: World Health Organization.

Australia New Zealand Food Authority, 2001. Pyrrolizidine alkaloids in food. A toxicological review and risk assessment. Canberra: ANZFA Australia

Betteridge K, Costall DA, Hutching SM, Devantier BP, Liu Y, 2000. Ragwort (Senecio jacobacea) control by sheep in a hill country bull beef system. Sheep Dairy News, 17(1):9-10; 9 ref

Brenchley WE, 1920. Weeds of Farm Land. London, UK: Longmans, Green and Co

Brennan AC, Harris SA, Tabah DA, Hiscock SJ, 2002. The population genetics of sporophytic self-incompatibility in Senecio squalidus L. (Asteraceae) I: S allele diversity in a natural population. Heredity, 89(6):430-438; 35 ref

Bull LB, Culvenor CCJ, Dick AT, 1968. The pyrrolizidine alkaloids. Amsterdam, Netherlands: North Holland Publishing Co

Cabrera AL, 1941. Compuestas bonaerenses. Revista del Museo de La Plata, 4:1-450

Cabrera AL, 1963. Flora de la Provincia de Buenos Aires. Parte VI. Compuestas. Buenos Aires, Argentina: Coleccion Cientifica del INTA

Cabrera AL, Ré RR, 1965. Sobre un Senecio adventicio en la provincia de Buenos Aires. Revista de la Facultad de Agronomia, Universidad Nacional de La Plata, 41:43-50

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Culvenor CCJ, 1985. Pyrrolidizine alkaloids: some aspects of the Australian involvement. Trends in Pharmacological Sciences, 6:18-22

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Delhey R, Kiehr DM, 1988. Puccinia lagenophorae as causal agent of rust in Senecio madagascariensis and S. vulgaris in the pampas. Malezas, 16:76-78

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Dickinson JO, King RR, 1978. Transfer of pyrrolizidine alkaloids from Senecio jacobaea into milk of lactating cows and goats. In: Keeler RF, James LF, van Kampen KR, eds. Effects of Poisonous Plants on Livestock. New York, USA: Academic Press, 201-208

Edgar JA, Röder E, Molyneux RJ, 2002. Honey from plants containing pyrrolizidine alkaloids: a potential threat to human health. Journal of Agricultural and Food Chemistry, 50:2718-2730

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Fernandez O, Montes L, 1987. A natural enemy of Senecio madagascariensis Pioret (Compositae). Fitopatologia, 22:37-38

Fernandez O, Verona C, 1984. Reproductive characteristics of Senecio madagascariensis Poiret (Compositae). Revista de la Facultad de Agronomia, Universidad de Buenos Aires, 5:125-137

Fu PP, Chou MW, Xia Q, Yang YC, Yan J, Doerge DR, Chan PC, 2001. Genotoxic pyrrolizidine alkaloids and pyrrolizidine alkaloid N-oxides - mechanisms leading to DNA adduct formation and tumorigenicity. Journal of Environmental Science and Health. Part C, Environmental Carcinogenesis & Ecotoxicology Reviews, 19(2):353-385; 165 ref

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Goeger DE, Cheeke PR, Schmitz JA, Buhler DR, 1982. Effect of feeding milk from goats fed tansy ragwort (Senecio jacobaea) to rats and calves. American Journal of Veterinary Research, 43(9):1631-1633

Goeger DE, Cheeke PR, Schmitz JA, Buhler DR, 1982. Toxicity of tansy ragwort (Senecio jacobaea) to goats. American Journal of Veterinary Research, 43(2):252-254

Green KR, 1953. Fireweed. The Agricultural Gazette of New South Wales, 64:527

Guillen D, Romero C, Montaldi ER, 1984. Germination of Senecio madagascariensis Poir. Revista de la Facultad de Agronomia, Universidad Nacional de La Plata, 60(1-2):5-9

Harding JDJ, Lewis G, Done JT, Allcroft R, 1964. Experimental poisoning by Senecio jacobaea in pigs. Pathologia Veterinaria, 1:204-220

Hartmann T, 1999. Chemical ecology of pyrrolizidine alkaloids. Planta, 207(4):483-495; 3 pp. of ref

Hartmann T, Zimmer M, 1986. Organ-specific distribution and accumulation of pyrrolizidine alkaloids during the life history of two annual Senecio species. Journal of Plant Physiology, 122(1):67-80

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Hind DJN, Jeffrey C, Scott AJ, 1993. Flore des Mascareignes 109. Composées. Royal Botanic Gardens, Mauritius, Paris, Kew: Sugar Industry Research Institute, Institut Français de Recherche Scientifique pour le Développement en Coopération (ORSTOM)

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Holtkamp RH, Hosking JR, 1993. Insects and diseases of fireweed, Senecio madagascariensis, and the closely related Senecio lautus complex. Proceedings of the 10th Australian and 14th Asian Pacific Weed Conference. Brisbane, Australia: Weed Society of Queensland, 104-106

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Hooper PT, 1978. Pyrrolizidine alkaloid poisoning-pathology with particular reference to differences in animal and plant species. In: Keeler RF, van Kampen KR, James LF, eds. Effects of Poisonous Plants on Livestock. New York, USA: Academic Press, 161-176

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Kinoshita S, Koyama H, Ogawa M, Michihito O, 1999. Senecio madagascariensis: A naturalized species in Japan. Acta Phytotaxonomica et Geobotanica, 50:12; 244-246

Launders TE, 1986. Competitive pastures and control of fireweed. Australian Weeds Research Newsletter, 35:42-43

Marohasy JJ, 1989. A survey of fireweed (Senecio madagascariensis Poir) and its natural enemies in Madagascar with a view to biological control in Australia. Plant Protection Quarterly, 4(4):139-145

Martin RJ, Colman RL, 1977. The effects of fertilizers, herbicides and grazing intensity on the incidence of firewood (Senecio lautus) in sub-tropical pastures. Australian Journal of Experimental Agriculture and Animal Husbandry, 17(85):296-300

Mattocks AR, 1986. Chemistry and toxicology of pyrrolizidine alkaloids. London, UK: Academic Press

Matzenbacher NI, Schneider AA, 2008. Note about an adventitious Senecio (Asteracae) in Rio Grande do Sul, Brazil. (Nota sobre a presença de uma espécie adventícia de Senecio (Asteraceae) no Rio Grande do Sul, Brasil.) Revista Brasileira de Biociências, 6(1):111-115.

Mayer F, Lüthy J, 1993. Heliotrope poisoning in Tadjikistan. The Lancet, 342:246-247

McEvoy PB, Cox CS, 1987. Wind dispersal distances in dimorphic achenes of ragwort, Senecio jacobaea. Ecology, USA, 68(6):2006-2015

McFadyen R, Sparks D, 1996. Biological control of fireweed. In: Shepherd RC, ed. Proceedings of the Eleventh Australian Weeds Conference. Melbourne, Australia: Weed Science Society of Victoria Inc., 305-308

McLean EK, 1970. The toxic actions of pyrrolizidine (Senecio) alkaloids. Pharmacological Review, 22:429-483

Medley K, 1997. Forest regeneration in the Tana River Primate National Reserve, Kenya. Journal of East African Natural History, 84:77-96

Molyneux RJ, James LF, 1990. Pyrrolizidine alkaloids in milk: thresholds of intoxication. Veterinary and Human Toxicology, 32(Suppl.):94-103; [Proceedings of the Symposium on Public Health Significance of Natural Toxicants in Animal Feeds, February 6-7, 1989, Alexandria, Virginia, USA.]; 54 ref

Olson BE, Lacey JR, 1994. Sheep: a method for controlling rangeland weeds. Sheep Research Journal, Special issue:105-112

Peterson JE, Culvenor CCJ, 1983. Hepatotoxic pyrrolizidine alkaloids. In: RF Keeler and AT Tu, eds. Handbook of natural toxins. Volume 1. Plant and fungal toxins. New York, USA: Marcel Dekker Inc., 637-671

Radford IJ, Cousens RD, 2000. Invasiveness and comparative life-history traits of exotic and indigenous Senecio species in Australia. Oecologia Berlin, 125:531-542

Radford IJ, King D, Cousens RD, 1995. A survey of Senecio madagascariensis Poir. (fireweed) density in pastures of coastal New South Wales. Plant Protection Quarterly, 10(3):107-111

Radford IJ, Liu Q, Michael PW, 1995. Chromosome counts for the Australian weed known as Senecio madagascariensis (Asteraceae). Australian Systematic Botany, 8(6):1029-1033; 21 ref

Radford IJ, Muller P, Fiffer S, Michael PW, 2000. Genetic relationships between Australian fireweed and South African and Madagascan populations of Senecio madagascariensis Poir. and closely related Senecio species. Australian Systematic Botany, 13(3):409-423; 39 ref

Ridker PM, Ohkuma S, McDermott WV, Trey C, J. HR, 1985. Hepatic veno-occlusive disease associated with consumption of pyrrolizidine alkaloid containing dietary supplements. Gastroentrology, 88:1050-1054

Rizk AFM, 1991. The pyrrolizidine alkaloids: plant sources and properties. In: Rizk AFM, ed. Naturally Occurring Pyrrolizidine Alkaloids. Boca Raton, Florida: CRC Press, 1-89

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Röder E, 1995. Medical plants in Europe containing pyrrolizidine alkaloids. Pharmazie, 50:83-98

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Seaman JT, Walker KH, 1985. Pyrrolizidine alkaloid poisoning of cattle and horses in New South Wales. Plant toxicology. Proceedings of the Australia-U.S.A. poisonous plants symposium, Brisbane, Australia, May 14-18, 1984., 235-246; 20 ref

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Sindel BM, 1996. Impact, ecology and control of the weed Senecio madagascariensis in Australia. In Caligari P, Hind DJN, eds. Proceedings of the International Compositae Conference, Kew, 1994. Vol. 2, Biology and Utilization. Kew, UK: Royal Botanic Gardens

Sindel BM, Michael PW, 1988. Survey of the impact and control of fireweed Senecio madagascariensis Poir. in New South Wales Australia. Plant Protection Quarterly, 3:22-28

Sindel BM, Michael PW, 1989. Frost as a limiting factor in the distribution of Senecio madagascariensis Poir. (fireweed) in Australia. Proceedings of 12th Asian Pacific Weed Science Society Conference. Taipei, Taiwan: Asian-Pacific Weed Science Society, 453-459

Sindel BM, Michael PW, 1992. Growth and competitiveness of Senecio madagascariensis Poir. (fireweed) in relation to fertilizer use and increases in soil fertility. Weed Research, 32:399-406

Sindel BM, Michael PW, 1992. Spread and potential distribution of Senecio madagascariensis Poir. Fireweed in Australia. Australian Journal of Ecology, 17:21-26

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Distribution References

CABI, Undated. CABI Compendium: Status inferred from regional distribution. Wallingford, UK: CABI

Cabrera A L, 1941. The Compositae of Baenos Aires. Revision of the Compositae of the Province of Buenos Aires, the federal capital and the Island of Martin Garcia. (Compuestas Bonaerenses. Revisión de las Compuestas de la Provincia de Buenos Aires, la capital federal y la Isla Martín García.). Revista del Museo de La Plata. 4 (Bot. No. 17), 1-450.

Hilliard OM, 1977. Compositae in Natal., Pietermaritzburg, South Africa: University of Natal Press.

Hind DJN, Jeffrey C, Scott AJ, 1993. (Flore des Mascareignes 109. Composées). In: Royal Botanic Gardens, Paris; Kew, Mauritius: Sugar Industry Research Institute, Institut Français de Recherche Scientifique pour le Développement en Coopération (ORSTOM).

Humbert H, 1963. (Flore de Madagascar et des Comores. 189e Famille - Composées)., Paris, France: Museum National D'Histoire Naturelle.

Kinoshita S, Koyama H, Ogawa M, Michihito O, 1999. Senecio madagascariensis: A naturalized species in Japan. In: Acta Phytotaxonomica et Geobotanica, 50 (12) 244-246.

López M G, Wulff A F, Poggio L, Xifreda C C, 2008. South African fireweed Senecio madagascariensis (Asteraceae) in Argentina: relevance of chromosome studies to its systematics. Botanical Journal of the Linnean Society. 158 (4), 613-620. DOI:10.1111/j.1095-8339.2008.00865.x

Matzenbacher N I, Schneider A A, 2008. Note about an adventitious Senecio (Asteracae) in Rio Grande do Sul, Brazil. (Nota sobre a presença de uma espécie adventícia de Senecio (Asteraceae) no Rio Grande do Sul, Brasil.). Revista Brasileira de Biociências. 6 (1), 111-115.

Medley K, 1997. Forest regeneration in the Tana River Primate National Reserve, Kenya. In: Journal of East African Natural History, 84 77-96.

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Sindel B M, Michael P W, McFadyen R E, Carthew J, 2008. The continuing spread of fireweed (Senecio madagascariensis) - the hottest of topics. In: Proceedings of the 16th Australian Weeds Conference, Cairns Convention Centre, North Queensland, Australia, 18-22 May, 2008. Queensland, Australia: Queensland Weed Society. 47-49.

Sindel B M, Radford I J, Holtkamp R H, Michael P W, 1998. The biology of Australian weeds. 33. Senecio madagascariensis Poir. Plant Protection Quarterly. 13 (1), 2-15.

Starr F, Martz K, Loope LL, 1999. New plant records from East Maui for 1998. In: Bishop Museum Occasional Papers, 11-15.

USDA-ARS, 2003. Hedychium flavescens. In: Germplasm Resources Information Network (GRIN). Online Database, Beltsville, USA: National Germplasm Resources Laboratory.

Witt A, Beale T, Wilgen B W van, 2018. An assessment of the distribution and potential ecological impacts of invasive alien plant species in eastern Africa. Transactions of the Royal Society of South Africa. 73 (3), 217-236. DOI:10.1080/0035919X.2018.1529003

Witt A, Luke Q, 2017. Guide to the naturalized and invasive plants of Eastern Africa. [ed. by Witt A, Luke Q]. Wallingford, UK: CABI. vi + 601 pp. DOI:10.1079/9781786392145.0000

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