Giant rat's tail grass (Sporobolus pyramidalis)

Giant rat’s tail grass is an upright grass that grows in clumps up to 1.7 m tall. It can take over pastures and invade bushland.

Profile

How does this weed affect you?

Giant rat’s tail grass is a weed in pastures and bushland areas, particularly on poorer soils.

Giant rat’s tail grass:

  • invades pastures, replacing more productive grasses
  • is tough and difficult for cattle to graze 
  • reduces feed intake and animal production in cattle
  • invades native grasslands, open woodlands, wetlands, replacing native plants
  • can increase fire intensity.

What does it look like?

Giant rat’s tail grass is a perennial upright grass that grows in clumps up to 1.5 m tall. It has seedheads that look a bit like a rat’s tail when young and may branch to a elongated pyramidal shape when mature.

Where is it found?

Giant rat’s tail grass is common in coastal northern New South Wales. It was probably accidently brought into Australia in contaminated pasture seed.

It is native to Africa.

Maps and records

  • Recorded presence of Giant rat's tail grass during property inspections (Map: Biosecurity Information System - Weeds, 2017-2020)
    These records are made by authorised officers during property inspections under the Biosecurity Act 2015. Officers record the presence of priority weeds in their council area and provide this to the NSW Department of Primary Industries. Records reflect the presence of the weed on the date of inspection.

  • Estimated distribution of Giant rat's tail grass in NSW (Map: NSW Noxious Weed Local Control Authorities, 2010)
    Map shows weed distribution and density estimated by local council weeds officers in 2010.

How does it spread?

Giant rat’s tail grass seeds become somewhat sticky when wet. Seeds spread:

  • by attaching to animals, clothing and vehicles
  • in water and mud
  • in contaminated agricultural produce such as pasture seed and fodder.

More information

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Control

Herbicide options

WARNING - ALWAYS READ THE LABEL
Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this information. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website www.apvma.gov.au

See Using herbicides for more information.


PERMIT 9792 Expires 30/11/2025
Glyphosate 360 g/L (Roundup®)
Rate: 3.3 L per 10 L of water
Comments: Wick wiper application. Apply when plant is actively growing.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate


Flupropanate 745 g/L (Tussock®)
Rate: 200 mL per 100L of water
Comments: Handgun application.
Withholding period: Don't graze cows or goats that are being milked on treated areas. Blanket sprayed pastures - grazing or cutting for stock feed - 120 days. Spot sprayed areas - grazing or cutting for stock feed - 14 days. Don't graze stock on treated areas for 14 days prior to slaughter.
Herbicide group: J, Inhibitors of fat synthesis (Not ACCase inhibitors)
Resistance risk: Moderate


Flupropanate 745 g/L (Tussock®)
Rate: 1.5–2.0 L/ha
Comments: Boom spray. Best results during late winter and early spring when desirable species are semi-dormant. Four month withholding period for blanket spray application.
Withholding period: Don't graze cows or goats that are being milked on treated areas. Blanket sprayed pastures - grazing or cutting for stock feed - 120 days. Spot sprayed areas - grazing or cutting for stock feed - 14 days. Don't graze stock on treated areas for 14 days prior to slaughter.
Herbicide group: J, Inhibitors of fat synthesis (Not ACCase inhibitors)
Resistance risk: Moderate


Glyphosate 360 g/L (Roundup®)
Rate: 10–15 mL per 1 L water
Comments: Handgun application for when plants are actively growing.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate


Glyphosate 360 g/L (Roundup®)
Rate: 6.0 L/ha
Comments: Boom application for pasture replacement/ improvement and best done as a split treatment. Apply when plants are actively growing.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate


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Biosecurity duty

The content provided here is for information purposes only and is taken from the Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.

Area Duty
All of NSW General Biosecurity Duty
All plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable.
Greater Sydney Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found.
Hunter Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found.
North Coast Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found.
This Regional Recommended Measure applies to Sporobolus jacquemontii (American rat's tail grass)
South East Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found.
*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfil the general biosecurity duty for this weed click here

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For technical advice and assistance with identification please contact your local council weeds officer.
For further information call the NSW DPI Biosecurity Helpline on 1800 680 244 or send an email to weeds@dpi.nsw.gov.au

Reviewed 2017