Weed Seed: Senecio madagascariensis (Madagascar ragwort)
- Prohibited Noxious, Class 1 in the Canadian Weed Seeds Order, 2016, 2016 under the Seeds Act. All imported and domestic seed must be free of Prohibited Noxious weed seeds.
- Listed on the List of Pests Regulated by Canada established under the Plant Protection Act.
Canadian: Absent from Canada (Brouillet et al. 2016Footnote 1).
Worldwide: Native to southern Africa and Madagascar and introduced to Argentina, Australia, Colombia, Japan, Kenya, Mauritius, Réunion and the United States (Hawaii) (CFIA 2014Footnote 2).
Duration of life cycle
Seed or fruit type
- Achene length: 2.0 – 2.5 mm
- Achene width: 0.5 mm
- Achene is oblong with narrow ends
- Several longitudinal ribs on achene surface.
- Surface roughened, appears sparkling under lights.
- Achene is dark yellow to reddish-brown
- Short, worm-like white hairs between the ribs of achene.
- Immature achenes have a long, white pappus 4.0 - 6.5 mm long.
Habitat and Crop Association
Colonizes a wide range of habitats, elevations and soil types. Often found in arid or moist pastures, coastal plains, yards, fields and roadsides (CFIA 2012Footnote 3).
Madagascar ragwort is a serious pest plant in Australia and Hawaii (Starr et al. 1999Footnote 4). This pioneer plant produces several thousands of seeds every year that are dispersed by wind or water (Starr et al. 1999Footnote 4). Infested pastures suffer lowered productivity through competition and toxicity to livestock (CABI 2016Footnote 5).
Common groundsel (Senecio vulgaris)
- Similar size, oblong shape and narrow ends.
- The surface hairs of common groundsel are long and dense; Madagascar ragwort has short, sparse hairs.
South African ragwort (Senecio inaequidens)
- Similar oblong shape, ribs and is closely related to Madagascar ragwort.
- South African ragwort can be up to 0.5 mm longer than Madagascar ragwort, has only one end narrowed and is usually dark brown and densely covered with long white hairs.
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