Native to the tropical Americas, tobacco weed is a vigorous and aggressive weed of agriculture in many wet tropical and subtropical countries. It smothers pasture with its seedlings and is a major threat to north Queensland's beef and dairy industries.
- Elephantopus scaber
- Slender, fast-growing herb up to 150cm tall.
- Leaves are oblong or oval, 10-20cm long, 2-5cm wide, mostly at base of plant.
- Leaf upper surfaces are rough, thinly covered in fine hairs.
- Leaf undersurfaces are densely haired, resinous, especially on veins.
- Flowers are small, white, many-headed clusters at tips of stems and side shoots.
- Leaf-like bracts are in cup of three each cluster.
- Flowers are tubular, 5 lobes at apex, about 4mm long.
- Stems are mostly erect, sparsely branched, becoming woody at base when mature,
- Stems have fine white hairs that may cause skin irritation when brushed against.
- Seeds are brown to greyish-black, 3mm long, each with 5 fine, straight, white, bristle-like hairs on top.
- Grows in fertile soils needing moderate to high rainfall.
Distribution in Queensland
- Found in Millaa Millaa area of southern Atherton Tableland, at Cape Tribulation in far north Queensland, Koumala district south of Sarina, and around Teemburra Dam west of Mackay.
- Seeds germinate any time of year in sufficient moisture.
- Flowering may also occur all year, but generally in May.
- Germination to reproduction time and time ungerminated seeds remains viable are not known; however, field observations indicate that seed banks build up in soil.
- Smothers healthy, thick pastures with dense masses of broadleafed seedlings.
- Major threat to beef and dairy industries of north Queensland.
How it is spread
- Seeds spread primarily by animals, machinery and running water.
- Controlled by cultivation.
- As no underground buds are produced, fire could kill a significant number of plants and may be useful during dry season.
- Slashing has been used to switch reproductive plants back to vegetative mode to allow treatment with herbicide.
- Spray plants before they develop flowering stems.
- Aerial spraying is an option when plants are inaccessible, but take care to prevent drift onto remnant and regenerating rainforest in paddock margins.
- Difficult to control once plant has begun to flower (and possibly as early as beginning of stem growth).
See the Tobacco weed fact sheet (PDF, 2.1MB) for herbicide control and application rates.
- No known biological control agents.
- This is a declared Class 2 species under the Land Protection (Pest and Stock Route Management) Act 2002.
- Taking for commercial use, introduction, keeping, releasing or supplying (including supplying things containing reproductive material of this pest) is prohibited without a permit issued by Biosecurity Queensland.
- Landholders are required to control declared pests on their properties.
- Last updated
- 03 December 2015