St. Barnaby's thistle (Centaurea solstitialis)
St Barnaby’s thistle is a summer growing annual. It can outcompete crops and pastures.
Profile
How does this weed affect you?
It will outcompete crops and pastures and dense patches can restrict stock movement.
Where is it found?
It is well established through many parts of NSW.
What does it look like?
St Barnaby’s thistle is an annual or short-lived plant, to 75 cm high. Flower heads are bright yellow surrounded by rows of yellow spines.
References
Parsons W.T. and Cuthbertson E.G. (1992) Noxious weeds of Australia. (Inkata Press, Melbourne).
More information
Control
Herbicide options
Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this information. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website www.apvma.gov.au
See Using herbicides for more information.
2,4-D LV ester 680g/L
(Estercide® Xtra)
Rate: 1.15 - 1.7 L per Hectare
Comments: Boom spray application
Withholding period: Do not graze or cut for stock food for 7 days after application.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate
Clopyralid 750 g/L
with
MCPA 500 g/L (Lontrel 750 SG Herbicide)
Rate: 20 or 28g/ha plus 1-1.5 L/ha MCPA amine (500 g/L)/ha
Comments: Spray rosette stage prior to stem elongation. For pasture and fallow land.
Withholding period: Do not graze or cut for stock food for 7 days after application. For harvesting up to 12 weeks, see label for details.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate
Fluroxypyr 140 g/L + Aminopyralid 10 g/L
(Various products)
Rate: 500 mL in 100 L of water
Comments: Hand gun application
Withholding period: Not required for pastures when used as directed. Do not graze or cut crops for stock food for 7 days after application. See label for export restrictions.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate
Glufosinate-ammonium 200 g/L
(Basta® )
Rate: 1.5–5.0 L/ha
Comments: Boom spray. Actively growing rosettes.
Withholding period: Variable, up to 16 weeks, see label for more information.
Herbicide group: 10 (previously group N), Inhibition of glutamine synthetase
Resistance risk: Moderate
Glufosinate-ammonium 200 g/L
(Basta® )
Rate: 500 mL in 100 L of water
Comments: Hand gun application
Withholding period: Variable, up to 16 weeks, see label for more information.
Herbicide group: 10 (previously group N), Inhibition of glutamine synthetase
Resistance risk: Moderate
Biosecurity duty
The content provided here is for information purposes only and is taken from the NSW Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.
| Area | Duty |
|---|---|
| All of NSW | General Biosecurity Duty All pest plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable. |
Reviewed 2025
