Chilean needle grass (Nassella neesiana)

Chilean needle grass grows in tussocks and produces spiky seeds. It takes over pastures and injures animals.

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How does this weed affect you?

Chilean needle grass:

• competes with pasture plants
• can halve pasture productivity during summer
• injures animals eyes and pierces hides
• downgrades wool
• can affect meat quality
• reduces biodiversity.

What does it look like?

Chilean needle grass grows in tussocks about 1 m high.

Leaves are:

• flat
• coarse or ribbed on the surface
• 1 – 5 mm wide
• with a small tuft of hairs at the junction of the leaf blade and leaf sheath.

Seeds are:

• pale brown when mature
• 8 – 10 mm long
• held inside two purple colour structures, 16 – 25 mm long called glumes
• very sharp at the end joining the stem
• with backwards pointing hairs at the stem end.

Chilean needle grass has a long bristle called an awn attached to the end of the seed further from the stem. The awn is:

• 6 – 9 cm long
• twisted when dry
• straight or with one or two distinctive bends
• difficult to pull off the seed
• surrounded by a corona of small teeth where it joins the seed. The corona teeth are 1 mm long.

Chilean needle grass also produces seeds in the nodes of the flowering stems. These stem seeds have a shorter awn, and account for about ¼ of seeds a plant produces.

Similar looking plants

Chilean needle grass looks like native spear grasses (Austrostipa spp.). It's related to serrated tussock (Nassella trichotoma) and Mexican feather grass (Nassella tenuissima). It can also look like other winter green grasses such as Danthonia and fescue.

Only Chilean needle grass has the corona of little ‘teeth’ where the awn joins the seed.

Where is it found?

In NSW, Chilean needlegrass is wide spread in the Central Tablalnds, Northern Tablelands and South East Regions. It also grows in the southern parts of the North West region, north west of the Hunter region, and eastern half of the Murray and Riverian regions. 

It was first identified in NSW during the early 1940s in the Glen Innes region. 

Chilean needle grass is native to South America. It is also found in New Zealand, South Africa and Europe.

What type of environment does it grow in?

Chilean needle grass mostly grows in grows in temperate and semi-arid regions. It is occasionally found in dry subtropical areas. It establishes best on bare ground, and can survive heavy grazing and drought. It has been found growing:

• in pastures
• in native grasslands
• in open woodlands
• along creekbanks. 
• in parks
• in disturbed areas such as roadsides, waste areas and drains.

Maps and records

• Recorded presence of Chilean needle grass during property inspections (Map: Biosecurity Information System - Weeds, 2017-2024)
  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.
  
  

How does it spread?

Animals, vehicles, and machinery spread Chilean needle grass seeds. The hairs at the sharp end of the seed anchor into in wool or fur. Seeds can stay attached to animals for months.

Hay baled from paddocks with Chilean needle grass may contain seeds. Seed comes from the flowers and along the nodes of the stalks.

Seeds can spread in floodwaters, and are only rarely dispersed by wind.

More information

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Control

The persistent seed bank makes Chilean needle grass difficult to control.

Long term control aims to stop the needle grass from seeding, and to reduce the soil seed bank. Control efforts should consider that:

• adult plants are long-lived and very hardy
• Chilean needle grass produces lots of seeds, and develops a long-lived seed bank
• it can produce flowers in the first season
• seed heads emerge during late spring
• most seeds have dropped from the plant by late February
• seeds can germinate year round, but mostly in autumn and spring
• seedlings grow slowly but most survive
• seeds buried deep remain viable for longer than those near the surface.

Control options include crop rotation, pasture management and herbicides.

Prevention

In areas without Chilean needle grass it’s important that infested fodder is not:

• sold or brought in
• scattered.

To reduce the chance of Chilean needle grass establishing you can:

• limit animal movement from infested areas into clean paddocks
• quarantine animals from infested areas, although not all seed will fall from animal coats.
• consider shearing sheep with Chilean needle grass in their wool before release
• seed bare soil areas with pasture species
• clean vehicles and machinery before moving into clean areas.

Early detection

Learn to identify Chilean needle grass. Control plants as soon as they appear and before they seed.

Physical removal

Remove isolated plants with a hoe where practical. This leaves less bare soil than spot spraying.

Pasture management

Maintaining healthy pastures is the best long-term defence against Chilean needle grass.  Thin and bare patches in the pasture are at most risk of invasion.

Growing fodder crops with weed control for 2 – 3 years can reduce the weed seed bank. This can improve the prospects for sowing new perennial pastures.

Grazing

Chilean needle grass provides an average quality feed.

In winter: graze heavily for short periods. Remove stock before they reduce desirable pasture species.  

In spring: graze heavily to reduce flower stalks. Sheep can graze spring spray-topped paddocks with less risk of wool contamination.

In summer: grazing does not help suppress the weed because flower stalks are unpalatable.

Chemical control

Most herbicides used to control Chilean needle grass contain either glyphosate or flupropanate. Pasture species have variable tolerance to these herbicides. Check which pasture species are present. Follow up is essential for successful control.

Chemical control may create bare patches where more needle grass will grow. This is more likely with glyphosate applications as it is considered a non-selective herbicide. However, flupropanate (consider a selective herbicide) can injure or suppress some desirable species and if applied to heavy Chilean needle grass infestations will leave large areas of bare soil due to effective control of widespread Chilean needle grass.

Regularly check and spot spray in pastures. Spot applications of flupropanate cause less damage to non-target plants.

In heavy infestations, graze during winter and weed wipe in spring.

Always observe grazing withholding periods following herbicide treatments in pastures.

Glyphosate herbicides

Glyphosate is not selective and readily damages other pasture plants if not directed correctly on Chilean needle grass. Glyphosate is more effective in autumn than in spring. Use glyphosate:

• in carefully targeted spot treatments
• for larger areas such as boom spraying in autumn before direct drilling or aerial seeding.
• the use of glyphosate is recommended for areas that are heavily infested with the weed because selective control will result in few desirable plants to re-establish the pasture.

Flupropanate herbicides

Flupropanate is more effective in spring than in autumn. Use flupropanate for:

• smaller infestations
• spot spraying
• spraying existing pastures.

Some pasture species are more sensitive to flupropanate in different seasons. For example phalaris is sensitive in autumn but not summer. At flowering, add the registered rate of glyphosate to flupropanate to help reduce seed set (for spot spraying only).

Spot spraying

Spot spray emerging seedlings, before plants set seed. Use a spray shield to minimise damage to surrounding plants. Check paddocks after spraying for any missed plants. Re-seed bare ground with pasture species.

Broadacre spraying

Herbicide can be applied with boomsprays or aircraft for larger areas. There is less chance of damage to non-target plants (particularly trees) using flupropanate.

Weed wipers

Weed wiping is less than 60% effective with Chilean needle grass. Wiping is best done soon after flowering (November) to stop seed set. Wiping is only effective if the needle grass is the tallest species in the paddock. Grazing management in September to October at set stocking rates will encourage the selective grazing of desirable species and allow the Chilean needle grass to grow taller, allowing a better height difference between weed and pasture.  

Herbicide resistance

Herbicide resistant plants spread and are harder to control. Herbicide resistance is more likely to develop when treating large areas with a lot of weeds. To avoid herbicide resistance:

• rotate flupropanate with glyphosate
• spray before seed set
• use other control methods with herbicide (cropping, more competitive pastures, chipping, forestry, cultivation where possible, grazing and fertiliser)
• reduce populations
• check weed survival after spraying and treat survivors with a different herbicide, and ensure survivors do not set more seed.

Herbicide options

See Using herbicides for more information.

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PERMIT 9792 Expires 30/11/2025
Flupropanate 745 g/L (Tussock®)
Rate: 500 mL / 10 L water
Comments: Wiper/wick use: Ensure weeds are at least 15 cm above species to be retained. Apply when weeds are actively growing. To avoid damage to desirable species; heavily graze 4-6 weeks prior to application. In ungrazed areas, slash or burn and allow for regrowth to target weeds. If possible conduct two passes in opposite directions. A repeat application may be required. Ground speed should not exceed 8 km/hr.
Withholding period: Spot spray: Do NOT graze or cut for stock feed for at least 14 days. Blanket spray: Do NOT graze, or cut for stock feed for at least 4 months. If stock are grazed in treated areas after required time has passed, remove stock from treated areas and do NOT slaughter or milk for human consumption until they have been on clean feed for at least 14 days.
Herbicide group: 15 (previously group J), Inhibition of very long chain fatty acid synthesis (VLCFA inhibitors)
Resistance risk: Moderate

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PERMIT 9792 Expires 30/11/2025
Glyphosate 360 g/L (Various products)
Rate: 1 L per 100 L water
Comments: Spot spray
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate

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PERMIT 9792 Expires 30/11/2025
Glyphosate 360 g/L (Various products)
Rate: 1 L/ha
Comments: Boom spray
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate

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PERMIT 9792 Expires 30/11/2025
Glyphosate 360 g/L (Various products)
Rate: 3.3 L /10 L water
Comments: Wiper / wick use: Ensure weeds are at least 15 cm above species to be retained. Apply when weeds are actively growing. To avoid damage to desirable species; heavily graze 4-6 weeks prior to application. In ungrazed areas, slash or burn and allow for regrowth to target weeds species. If possible conduct two passes in opposite directions. A repeat application may be required. Ground speed < 8 km/hr.
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate

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Flupropanate 745 g/L (Tussock®)
Rate: 1.5–3.0 L/ha
Comments: Boom application. Apply to actively growing plants.
Withholding period: Spot spray: Do NOT graze or cut for stock feed for at least 14 days. Blanket spray: Do NOT graze, or cut for stock feed for at least 4 months. If stock are grazed in treated areas after required time has passed, remove stock from treated areas and do NOT slaughter or milk for human consumption until they have been on clean feed for at least 14 days.
Herbicide group: 15 (previously group J), Inhibition of very long chain fatty acid synthesis (VLCFA inhibitors)
Resistance risk: Moderate

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Flupropanate 745 g/L with Glyphosate 360 g/L (Various products)
Rate: 200 mL flupropanate plus 150 mL glyphosate 360g/L per 100 L of water
Comments: Spot spray application. Apply to actively growing plants.
Withholding period: Spot spray: Do NOT graze or cut for stock feed for at least 14 days. Blanket spray: Do NOT graze, or cut for stock feed for at least 4 months. If stock are grazed in treated areas after required time has passed, remove stock from treated areas and do NOT slaughter or milk for human consumption until they have been on clean feed for at least 14 days.
Herbicide group: 15 (previously group J), Inhibition of very long chain fatty acid synthesis (VLCFA inhibitors)
Resistance risk: Moderate

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Flupropanate 86.9 g/kg (GP Flupropanate)
Rate: 22.5 kg/ ha
Comments: Apply February to December inclusive. Apply to actively growing and stress free plants. Graze to reduce cover of desirable species before application.
Withholding period: Do not graze or cut for stock feed areas which have received any treatment other than spot treatment for at least 4 months. Spot treatment: Do not graze or cut for stock feed for at least 14 days. If stock are grazed in treated areas after required time has passed, remove stock from treated areas and do NOT slaughter or milk for human consumption until they have been on clean feed for at least 14 days. This requirement applies permanently to treated areas.
Herbicide group: 15 (previously group J), Inhibition of very long chain fatty acid synthesis (VLCFA inhibitors)
Resistance risk: Moderate

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Flupropanate 86.9 g/kg (GP Flupropanate)
Rate: 2.25 g per square metre
Comments: Spot application: apply year round. Apply to actively growing and stress free plants. Graze to reduce cover of desirable species before application.
Withholding period: Do not graze or cut for stock feed areas which have received any treatment other than spot treatment for at least 4 months. Spot treatment: Do not graze or cut for stock feed for at least 14 days. If stock are grazed in treated areas after required time has passed, remove stock from treated areas and do NOT slaughter or milk for human consumption until they have been on clean feed for at least 14 days. This requirement applies permanently to treated areas.
Herbicide group: 15 (previously group J), Inhibition of very long chain fatty acid synthesis (VLCFA inhibitors)
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 pest 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.
All of NSW	Prohibition on certain dealings Must not be imported into the state, sold, bartered, exchanged or offered for sale.
Central Tablelands An exclusion zone is established for Mid-Western Regional Council and Orange City Council areas. A core infestation area is established for Bathurst Regional Council, Blayney Council, Cabonne Council and Cowra Shire Council, Lithgow Council and Oberon Council.	Regional Recommended Measure* (for Regional Priority - Containment) Within exclusion zone: Land managers should mitigate the risk of the plant being introduced to their land. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Within core infestation area: Land managers should mitigate the risk of the plant being introduced to their land. Land managers should mitigate spread of the plant from their land. A person should not buy, sell, move, carry or release the plant into the environment. Land managers should reduce the impact of the plant on assets of high economic, environmental and/or social value.
Central West	Regional Recommended Measure* (for Regional Priority - Eradication) Land managers should mitigate the risk of the plant being introduced to their land. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found.
Hunter	Regional Recommended Measure* (for Regional Priority - Eradication) Notify local control authority if found. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant.
Murray Core infestation zone: Albury City Council, Greater Hume Council, Federation Council, Murrumbidgee Council, Snowy Valleys Council. Exclusion zone: Berrigan Shire Council, Edward River Council, Murray River Council.	Regional Recommended Measure* (for Regional Priority - Containment) Within exclusion zone: Land managers should mitigate the risk of the plant being introduced to their land. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found. Within core infestation area: Land managers should mitigate the risk of the plant being introduced to their land. Land managers should mitigate spread of the plant from their land. A person should not buy, sell, move, carry or release the plant into the environment. Land managers should reduce the impact of the plant on assets of high economic, environmental and/or social value.
North West An exclusion zone is established for all lands in the region, except the core infestation area comprising lands within the Tamworth Regional Council.	Regional Recommended Measure* (for Regional Priority - Containment) Whole of region: Land managers mitigate the risk of new weeds being introduced to their land. Within exclusion zone: Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found. Within core infestation: Land managers should mitigate spread of the plant from their land. A person should not buy, sell, move, carry or release the plant into the environment. Land managers should reduce the impact of the plant on assets of high economic, environmental and/or social value.
Riverina	Regional Recommended Measure* (for Regional Priority - Eradication) Land managers should mitigate the risk of the plant being introduced to their land. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found. Your local biosecurity weeds officer can help to identify, advise on control, and how to remove this weed.
	*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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Reviewed 2023