Soldier thistle (Picnomon acarna)


How does this weed affect you?

Soldier thistle, native to southern Europe and south-western Asia is a prickly, upright, annual thistle usually growing to 50-75 cm tall but occasionally reaching 100 cm in height. It forms a basal rosette (cluster) of leaves during the early stages of growth. The rosette leaves are slightly lobed, with distinct short yellow spines, and grow to 30 cm long. The stems and leaves are densely covered in white hairs that give them a cobwebby or woolly appearance.

Soldier thistle competes with cereal crops and interferes with harvesting by clogging machinery. Its sharp spines can injure sheep, dogs and humans and decrease suitable grazing areas for stock.

Soldier thistle is a weed of roadsides, waste areas, channel banks, crops and pastures in temperate and occasionally also semi-arid environments.

It can be controlled by hand grubbing, cultivating, mowing, slashing or treating with herbicides before the flowering head develops.

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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

See Using herbicides for more information.

Glyphosate 360 g/L (Roundup®)
Rate: 10 mL per 1 L water
Comments: Spot spray
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate

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Biosecurity duty

The content provided here is for information purposes only and is taken from the 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 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.

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For technical advice and assistance with identification please contact your local council weeds officer.
For further information call the NSW DPI Biosecurity Helpline on 1800 680 244 or send an email to

Reviewed 2018