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Gamba grass (Andropogon gayanus)

A tall tropical grass that creates fuel loads several times higher than native grasses, driving hot late-season fires that kill trees and threaten infrastructure.

Key facts

Type: Weed, grass.

Native to: Tropical Africa.

Established in: QLD, WA, NT.

Best time to act: Treat during the wet season while the grass is green and growing.

Identification

  • Large perennial tussock grass that can exceed 4 m in height.
  • Leaves up to 1 m long with a distinctive white midrib.
  • Fluffy seed heads in V-shaped pairs.

Where it grows

Savanna woodland, roadsides and disturbed land in the wet-dry tropics.

Why it matters

  • Intense fires that change woodland to grassland.
  • Increases fire risk to power lines, mines and communities.
  • Displaces native grasses.

How it spreads

  • Wind, water and vehicles carry seed.
  • Planted as pasture in the past.

Control options

  • Spot spray or treat with registered herbicides during the wet season when plants are actively growing.
  • Manage infestations near assets and boundaries first.
  • Follow-up over several seasons.

Hygiene and washdown

  • Clean vehicles and slashers used on infested roads before moving to clean country.
  • 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): Weed of National Significance. One of 32 nationally agreed priority weeds, managed through national strategies with all states and territories. Key threatening process. Listed under the EPBC Act, with a national threat abatement plan for invasion by five invasive grass species.
  • Queensland: Restricted matter, category 3. Do not give it away, sell or release it into the environment. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: Prohibited matter. It is an offence to deal with it, and you must notify NSW DPIRD as soon as you become aware of it.
  • 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: Declared pest (C2), prohibited. C2 Eradication: present in limited areas and targeted for eradication. It must not be brought into WA (prohibited organism).
  • Tasmania: Declared weed. Property managers are required by law to control declared weeds, and their import and sale are prohibited.
  • Northern Territory: Declared weed, Class A and B. Class A: to be eradicated. Class B: growth and spread must be controlled. All declared weeds are also Class C, so they must not be brought into the NT.
  • Australian Capital Territory: Declared pest, notifiable, prohibited. It is a declared pest throughout the ACT. You must report it to ACT Biosecurity. Dealing with it, such as selling, moving or keeping it, is prohibited.

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)
  • Western Australia: Biosecurity and Agriculture Management Act 2007 (WA), administered by the WA Department of Primary Industries and Regional Development
  • Northern Territory: Territory Parks and Wildlife Conservation Act 1976 (NT), administered by NT Department of Lands, Planning and Environment

Sources