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:

  • takes over pastures
  • can halve productivity during summer
  • injures animals eyes
  • downgrades wool
  • pierces hides
  • 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?

The main infestations are in the:

  • Northern Tablelands and north-west slopes
  • Southern Tablelands and southwest slopes.

It was first identified in NSW during the early 1940s in the Glen Innes region. In 1996, there was a major infestation near Tamworth in the Reedy Creek catchment.

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 needlegrass grows in:

  • pastures
  • native grasslands.

It establishes best on bare ground, and can survive heavy grazing and drought.

Distribution map

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.

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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 needlegrass 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

Fluproaonate is more effective in spring than in autumn. Use fluproponate 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

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 30/11/2020
Glyphosate 360 g/L (Roundup®)
Rate: 1 L per 100 L water
Comments: Spot spray
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate


PERMIT 9792 Expires 30/11/2020
Glyphosate 360 g/L (Roundup®)
Rate: 1 L/ha
Comments: Boom spray
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate


Flupropanate 745 g/L (Tussock®)
Rate: 1.5–3.0 L/ha
Comments: Boom application. Apply to actively growing plants.
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 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: 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


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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.
All of NSW Prohibition on dealings
Must not be imported into the State or sold
Central Tablelands
Exclusion zone: whole region except for the core infestation area of Bathurst Council, Blayney Council, Lithgow Council, Oberon Council, Cabonne Council and Cowra Council
Regional Recommended Measure*
Whole region: The plant should not be bought, sold, grown, carried or released into the environment. Exclusion zone: The plant should be eradicated from the land and the land kept free of the plant. Land managers should mitigate the risk of the plant being introduced to their land. Core infestation area: Land managers should mitigate spread from their land. Land managers reduce impacts from the plant on priority assets.
Central West 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.
Murray Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. Plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found.
North West
An exclusion zone is established for all lands in the region, except the core infestation area comprising the Tamworth Regional council
Regional Recommended Measure*
Whole of region: The plant should not be bought, sold, grown, carried or released into the environment. Exclusion zone: Land managers should mitigate the risk of new weeds being introduced to their land; land managers should mitigate spread from their land. Core infestation: Land managers reduce impacts from the plant on priority assets
Northern Tablelands Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. Land managers should mitigate spread from their land. The plant should not be bought, sold, grown, carried or released into the environment.
Riverina Regional Recommended Measure*
Land managers should mitigate the risk of the plant being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant.
South East
Exclusion zone: whole of region except core infestation area of Wollongong, Kiama, Shellharbour, Wingecarribee, Gouburn/Murwaree, and Queanbeyan/Palerang
Regional Recommended Measure*
Whole region: Land managers should mitigate the risk of new weeds being introduced to their land. Exclusion zone: The plant should be eradicated from the land and the land kept free of the plant.
*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfill 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 2018