Pacific Pests, Pathogens and Weeds - Online edition

Pacific Pests, Pathogens, Weeds & Pesticides

Fireweed (501)

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  • Worldwide distribution. In Australia, but NOT in Pacific island countries.
  • Aggressive weed especially in pastures (poor nutrition, overgrazed or following drought), cultivated land, open woodlands, grasslands, parks, wastelands, roadsides. Massive early (6-10 weeks) seed production. Environmental weed in competition with native species. Economic impacts from poisoning cattle (acute and chronic): lower carrying capacity, weed management, changing from dairy and beef to sheep/goats. Horses susceptible.
  • Spread: stems root from nodes, seed on the wind, birds, animals (including stock), on clothing, and contaminant (hay, other seeds, machinery, vehicles).
  • Biosecurity: check pasture seed.
  • Biocontrol: none.
  • Cultural control: hand-weeding, slashing; maintain vigorous healthy pastures, do not overgraze; use sheep/goats; clean machinery/vehicles; use only weed-free hay, and monitor.
  • Chemical control: in Australia, 2,4-D; metsulfuron-methyl; bromoxynil; bromoxynil + aminopyralid; bromoxynil + diflufenican; fluroxypyr + aminopyralid; picloram + triclopyr + aminopyralid.
Common Name

Fireweed. It is also known as Madagascar fireweed, Madagascar ragwort.

Scientific Name

Senecio madagascariensis. It is a member of the Asteraceae.

AUTHOR Grahame Jackson
Information from PIER (2017) Senecio madagascariensis Poir., Asterasceae. Pacific Island Ecosystems at Risk (PIER), Institute of Pacific Islands Forestry. (; and CABI (2019) Senecio madagascariensis (fireweed). Invasive Species Compendium. (; and Fireweed (Senicio madagascariensis) (2019) NSW WeedWise. Department of Primary Industries, NSW Government. (; and DAF (2020) Fireweed Senecio madagascariensis. Queensland Government. (; and from Senecio madagascariensis (2016) Weeds of Australia, Biosecurity Queensland Edition. Queensland Government. ( Photo 1 Forrest & Kim Starr, Starr Environmental, Photo 2 John Tann Fireweed Groundsel leaves: ( Photo 3 Juan Campá, MGAP, ( Photo 4 John Robert McPherson: ( Photo 5 Forrest & Kim Starr, Photo # starr-001228_0149): (

Produced with support from the Australian Centre for International Agricultural Research under project HORT/2016/185: Responding to emerging pest and disease threats to horticulture in the Pacific islands, implemented by the University of Queensland and the Secretariat of the Pacific Community.

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