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Fringed dodder (Cuscuta suaveolens)

Fringed Dodder is a parasitic weed that can seriously affect crops and pastures, especially lucerne, clover and other legumes. It can also infest native vegetation and has the potential to become an environmental weed.

Key facts

Type: Weed, vine and creeper.

Native to: Southern Brazil, Argentina, Chile and Uruguay.

Established in: NSW, VIC, SA.

Other names: Chilean Dodder, Chile Dodder, Lucerne Dodder, Alfalfa Dodder.

Best time to act: Most seed germination occurs in late spring, and flowering takes place from late spring through early autumn.

Identification

  • It is a short-lived, leafless plant that twines over other plants and can form a dense mat.
  • Its thin, hairless, thread-like stems are usually yellowish-green, cream or whitish, with small suckers that penetrate host stems or leaves.
  • Its small cream-to-white, bell-shaped flowers are 3–4 mm long and grow in loose clusters on stalks 3–6 mm long.
  • Its greenish-yellow capsules are 2–3 mm across and contain up to four rounded, granular seeds.
  • Look-alike: It resembles introduced Dodders such as Cuscuta campestris, C. planiflora and C. epithymum, and native Dodders including C. australis, C. chinensis, C. tasmanica and C. victoriana. Loose flower clusters on 3–6 mm stalks distinguish it from most, while Tasmanian Dodder (C. tasmanica), which shares this feature, has larger, blunt-tipped petals 4–6 mm long.
  • Look-alike: Native Dodder laurels (Cassytha species) are also parasitic twiners, but have three petals and three sepals, 6–9 stamens and fleshy, one-seeded fruit.

Where it grows

In Australia it is naturalised in parts of south-eastern Australia, including NSW, southern Victoria, Tasmania and south-eastern South Australia, and occurs in crops, pastures, grasslands, roadsides and saline habitats.

Why it matters

  • It is a potentially significant parasite of crops and pastures, mainly attacking lucerne, clovers and other legumes, and has also been recorded on carrots and onions.
  • Infested areas are often quarantined, causing financial losses, and contaminated produce has reduced value.
  • It has infested native vegetation in south-eastern South Australia and NSW, including lignum thickets and gidgee woodlands in Culgoa National Park.
  • It is listed as an agricultural sleeper weed with potential for nationally significant agricultural impacts if it spreads.

How it spreads

  • It reproduces by seed and sometimes by stem fragments; these can be carried to new areas in contaminated agricultural produce and washed downstream by water.
  • Seeds can also spread in mud attached to vehicles and can pass intact through animals’ digestive tracts.
  • Contaminated pasture seed, hay and grain, livestock and machinery can all spread it between properties or paddocks.

Control options

  • Prevent introduction and spread with good quarantine measures, and destroy contaminated produce.
  • Clean machinery before moving it to another paddock, and keep stock from infested areas in quarantine for at least two days before moving them to Dodder-free pasture.
  • Where practical, replace or rotate severely infested crops or pastures with less susceptible or resistant options; do not sow lucerne or susceptible legumes again for at least five years when using rotations for control.
  • Cut the host plant as close to ground level as possible and burn it; registered contact herbicides can be used to rapidly desiccate the standing crop and destroy Dodder plants.

Hygiene and washdown

  • Clean machinery before moving between paddocks, and destroy contaminated pasture seed, hay and grain rather than moving it to clean areas.
  • Keep livestock from infested areas quarantined for at least two days before moving them to Dodder-free pasture.
  • 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: 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: Not listed. Not found in the Western Australian Organism List. Check with DPIRD before moving or keeping it.
  • 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.

  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development
  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria
  • South Australia: Landscape South Australia Act 2019 (SA), administered by the regional landscape board

Sources