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Chilquilla (Baccharis glutinosa)

Chilquilla is currently known in Australia from an infestation of about 4 ha near Maryborough, Victoria, where it has a relatively slight effect on pasture and cereal production. It is an agricultural sleeper weed with potential to become a weed of irrigated crops and to have nationally significant agricultural impacts if it spreads.

Key facts

Type: Weed, herb.

Native to: Chile, Argentina and Brazil.

Established in: VIC.

Other names: Baccharis pingraea.

Identification

  • It is a robust herb or sub-shrub up to about 1 m high, arising from a strong, branching rootstock that can produce new stems.
  • Stems appear to die down annually; the stems and leaves have no hairs but may be covered in slightly sticky resin.
  • Leaves are mostly 2–8 cm long and 2–8 mm wide, usually with 3–8 narrow teeth or lobes on each side.
  • White flowers grow in cup-shaped heads, usually in loose clusters of about 5–15 at stem ends; male and female flowers grow on separate bushes.
  • Look-alike: Similar species include aster-weed (Aster subulatus) and fleabanes (Conyza spp.), particularly C. sumatrensis and C. bonariensis: the latter two are somewhat hairy along their stems, while aster-weed has short, distinct ray florets.

Where it grows

In Victoria it occurs in pasture, has been recorded in an oat crop, and some plants grow in a shallow drainage channel near Maryborough.

Why it matters

  • Its current impact at the Victorian site is relatively slight, reducing somewhat the capacity to carry stock and/or produce cereal grain.
  • Like other Baccharis species, it could become persistent in flood plains, old fields or similar habitats.
  • It is a weed of irrigated crops overseas and is climatically suited to irrigation regions in Australia.
  • It is one of seventeen sleeper weeds identified as having potential for nationally significant agricultural impacts if allowed to spread.

How it spreads

  • Because plants in Victoria appear not to produce seed, spread there is thought to be confined to transport of whole plants or fragments of the regenerative rootstock.
  • Plants can resprout from the rootstock and survive significant disruption.
  • Future outbreaks are likely to be near waterways or in seasonally inundated sites.

Control options

  • Limited control has been attempted at the Victorian site, including slashing, grazing and limited chemical application.
  • Plants are able to resprout from the rootstock.
  • No biological control agent is listed.
  • For chemical information, consult the Australian Pesticides and Veterinary Medicines Authority.

Hygiene and washdown

  • Prevent the movement of whole plants or fragments of regenerative rootstock between sites, as these are the reported means of spread in Victoria.
  • 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: Not listed. Not found in the Western Australian Organism List. Check with DPIRD before moving or keeping it.
  • 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.

  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria

Sources