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Crow garlic (Allium vineale)

Crow garlic is an agricultural weed in Australia that can taint cereal grain, milk and meat with a strong garlic odour and flavour. It also occurs in some native vegetation and is difficult to eradicate because bulbs and bulbils can remain dormant or regenerate over several years.

Key facts

Type: Weed, herb.

Native to: Europe, North Africa and Asia Minor.

Established in: VIC, TAS, SA, WA.

Other names: False Garlic, Field Garlic, Stag's Garlic, Wild Garlic.

Best time to act: Look for new growth after the first autumn rains and through winter and spring, and control plants before bulbils drop from the heads in late summer.

Identification

  • It is an erect, strong garlic-smelling perennial herb, usually with a single stem, growing 300 mm to 1.2 m high.
  • The stems are hollow and cylindrical, and the plant has 2–4 hollow, almost cylindrical leaves that later become grooved on the upper surface.
  • Its flowering head is a dense, round umbel, often made up mostly of brown, smooth, shiny bulbils rather than flowers.
  • Crushing the plant releases a strong garlic smell; small bulbs may also be found around the main bulb.

Where it grows

In Australia it occurs in pastures, cereal crops, vineyards, roadsides and some native vegetation, often on poorly drained, heavy soils and riverbanks.

Why it matters

  • Its garlic odour and flavour can taint grain, grain products, milk and meat; contaminated wheat may be rejected at silos and contaminated barley is unsuitable for malting.
  • Bulbils are difficult to remove from harvested grain, and infested grain milled for stockfeed can clog mill rollers.
  • It invades or occurs in some native vegetation and is regarded as an environmental weed in South Australia, New South Wales, Tasmania and Victoria.
  • Crow garlic is suspected of causing cattle poisoning in Britain, and field garlic has caused poisoning in some mammals; dogs are reported to be particularly susceptible.

How it spreads

  • Bulbs, bulbils and seeds can spread in contaminated hay or grain, on machinery and animals, and in water.
  • Bulbils resemble wheat grains and are difficult to remove during cleaning, so transporting and planting contaminated wheat has contributed to its wide distribution.
  • Aerial bulbils fall to the ground when the plant's above-ground parts die in late summer.

Control options

  • Use an integrated program of cultivation, grazing and registered herbicides over several years; a program of at least five years may be needed to eradicate the weed.
  • Prevent aerial bulbils and seed from forming, and remove plants before bulbils drop; for small infestations, remove all bulbs and bulblets as well.
  • Repeat cultivation over several years, preferably alongside chemical treatment, because some bulbs may remain dormant for up to six years.
  • Grazing by sheep or cattle can reduce plants but will not kill underground bulbs; take care because of the risk of stock poisoning.

Hygiene and washdown

  • Check and clean machinery after working infested areas, and avoid moving contaminated hay or grain to uninfested sites.
  • Take care not to drag bulbs into new areas during tillage.
  • 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: Restricted weed. Where it is a restricted weed, trade in it (including the plant, its seed or contaminated material) is prohibited.
  • South Australia: Declared plant. Depending on the declaration, it can be an offence to move it on public roads or sell it, and landowners may be required to control it on their land.
  • 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: Declared weed. Property managers are required by law to control declared weeds, and their import and sale are prohibited.
  • Northern Territory: Not declared. Not on the NT A to Z weed list, and Weeds Australia does not list it as declared in the NT. Check the NT declared weeds list before moving or planting it.
  • 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.

  • 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