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Wild radish (Raphanus raphanistrum)

Wild radish is one of Australia’s most widespread and serious agricultural weeds, particularly in cereal and pulse crops. It competes with crops, contaminates grain and is difficult and expensive to control; it is also resistant to several herbicide groups in Australia.

Key facts

Type: Weed, herb.

Native to: Mediterranean region.

Established in: QLD, NSW, ACT, VIC, TAS, SA, WA.

Other names: Jointed Charlock.

Best time to act: Look for seedlings mainly in autumn and winter, when most seeds germinate, and control plants before they produce seed.

Identification

  • An upright annual herb, usually about 500 mm tall but occasionally recorded up to 1.5 m.
  • Stems and leaves are covered in stiff hairs and feel rough to touch.
  • Lower leaves are deeply lobed, with a large terminal lobe; leaves become smaller higher up the stem.
  • Flowers have four yellow or white petals, sometimes pink, usually with purple veins.
  • Long, narrow fruits have constrictions between the seeds and break at these points when ripe into hard, ribbed, one-seeded units.
  • Look-alike: It may be mistaken for yellow-flowered brassica-like species in the genera Brassica, Diplotaxis, Rapistrum and Sinapis.
  • Look-alike: Mature wild radish fruits have obvious constrictions between the seeds and break into hard, ribbed, one-seeded units, which distinguishes them from similar species.

Where it grows

Across Australia it occurs in cereal and grain legume crops and disturbed places such as roadsides, waste places and vacant land, with a broad distribution from Queensland through the southern states and into southern Western Australia.

Why it matters

  • It can substantially reduce crop yields and competes vigorously for light, nutrients and moisture.
  • Its tough stems interfere with harvesting, and its seeds are difficult to separate from grain, causing contamination.
  • It is relatively unpalatable to stock and can poison livestock; in pastures, it can taint meat and dairy products.
  • It can act as a host or reservoir for pests and pathogens of grain crops.

How it spreads

  • Wild radish reproduces only by seed, and can produce up to 45,000 seeds per square metre.
  • Seeds can spread by water and in contaminated soil, fodder, vehicles and cultivation equipment, and may be moved along roadsides during maintenance.
  • Seeds are difficult to clean from harvested cereals, so contaminated agricultural produce is an important means of spread.

Control options

  • Target control at preventing seed production and depleting existing seed banks.
  • Use registered herbicides as part of an integrated approach with non-chemical control.
  • Hand remove isolated plants, or use methods such as mulching, hoeing and burning.
  • Repeated cultivation can help deplete the seed bank, but cultivation alone is not effective in crops and can damage soil structure and increase erosion risk.

Hygiene and washdown

  • Clean cultivation and harvesting equipment, sow clean crop seed, and avoid moving contaminated soil or fodder to uninfested areas.
  • Quarantine stock that may have eaten fruiting material.
  • Inspect and clean vehicles, plant and footwear before leaving an infested area, paying attention to tyres, radiators, belly plates, tracks and floor mats.
  • Wash down at a designated bay where runoff is contained and can be monitored for seedlings.
  • Record each washdown so the client has evidence of clean entry and exit.

Classification by state

  • Australia (national): No national listing. Managed under state and territory law.
  • Queensland: Not prohibited or restricted. Not listed as prohibited or restricted matter in Queensland. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: Not a priority weed. Not a state or regional priority weed in NSW. The general biosecurity duty applies: anyone dealing with it must prevent, eliminate or minimise the risk it poses.
  • Victoria: Not declared. Not declared under the Catchment and Land Protection Act 1994. Other Victorian laws may still apply.
  • South Australia: Not declared. Not declared under the Landscape South Australia Act 2019. Other laws may still apply.
  • Western Australia: Permitted, not declared. Listed as a permitted organism in WA, so it can be brought in, but it is not a declared pest.
  • Tasmania: Not declared. Not a declared weed in Tasmania. Other laws may still apply.
  • Northern Territory: Check NT list. There is no NT weed profile for it. Check the NT declared weeds list for its current status.
  • Australian Capital Territory: Not declared. Not declared under the Biosecurity Act 2023 (ACT). A general biosecurity duty still applies.

Legal obligations

Every state and territory places a duty on landholders and people working on land to prevent the spread of invasive species, such as the general biosecurity obligation in Queensland and the general biosecurity duty in New South Wales. Declarations and control requirements differ between states and local government areas, so check the current official list before work starts.

  • Queensland: Biosecurity Act 2014 (Qld), administered by Biosecurity Queensland (13 25 23)
  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development
  • Australian Capital Territory: Biosecurity Act 2023 (ACT), administered by ACT Biosecurity
  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria
  • Tasmania: Biosecurity Act 2019 (Tas), administered by Biosecurity Tasmania
  • South Australia: Landscape South Australia Act 2019 (SA), administered by the regional landscape board
  • Western Australia: Biosecurity and Agriculture Management Act 2007 (WA), administered by the WA Department of Primary Industries and Regional Development

Sources