Espartillo - broad kernel (Amelichloa caudata)

Profile

Impact

Espartillo is an invasive perennial tussock grass that invades pastures, native grasslands and stream banks in temperate climates.

Espartillo is unpalatable and has little nutritive value for stock. It has infested pastures, native grasslands, riparian areas and other areas of environmental importance. It is also known to invade lucerne crops.

Found along roadsides and disturbed areas, it can quickly encroach into neighbouring properties and bushland, particularly if there is a lot of bare ground. Once established, espartillo is a difficult weed to manage and control.

Distribution

Native to Argentina, Chile and Uruguay, espartillo is considered a weed in New Zealand, USA, Italy and Spain. In its native range of Argentina and in California, USA, it  is a troublesome weed of lucence crops.

Espartillo was first recorded in NSW in the 1950s and is present in a few localised areas of NSW. The concern with espartillo is that under the right conditions, it may quickly increase its range and density. It is now found throughout the Riverina, western slopes and plains regions of NSW. It is of particular concern in the New England and Liverpool Plains regions of the state.

In Victoria, espartillo is mostly located in the central districts of Maryborough, Dunolly and Clunes where it continues to spread. In Tasmania it is located as isolated infestations on Flinders Island and near Hobart, and is subject to an eradication program.

This species has a much wider distribution than Amelichloa brachychaeta.

Spread

Espartillo reproduces only by seed. Seeds are produced in open pollinated panicle seedheads and in self-pollinated spikelets at the base of the plant.  Most spread is by stock, wildlife and humans. Seeds have awns that can attach to fur, wool and clothing. Seed can also be spread by vehicle movement and water.

Lifecycle

A perennial grass. Seeds germinate in autumn and seedlings grow slowly through the winter. Growth rates increase during spring. Flowering stems develop in late spring and continue throughout the summer, provided enough moisture is available. Growth slows again or even ceases during the following winter, with new tillers developing in the spring.

Description

An erect tussock forming grass that grow 75–100 cm high. Broad kernel espartillo is very similar to narrow kernal espartillo (Amelichloa brachychaeta), and the two species are difficult to tell apart, except for the following differences:

  • Broad kernal espartillo has a partly hairy seed coat; and a grain that is relatively broad (2-3 mm long and 1-1.4 mm wide). It produces stem seeds only in the lower leaf sheafs. 
  • Narrow kernal espartillo has a completely hairy seed coat; and a grain that is relatively narrow (2-3 mm long and  0.9-1.0 mm wide). It produces stem seeds in both the upper and lower leaf sheaths.

Espartillo is also similar in appearance to the native spear grass.

If left untreated, espartillo tussocks can grow up to 1 m wide. The centre of the plant dies back, leaving a seed rich mulch.

Leaves

  • leaf blade is stiff, flattened or tightly rolled, up to 50 cm long and 1.5–2.5 mm wide, rough to touch
  • leaf sheath is smooth on the surface with hairy edges
  • ligule (membranous structure where the leaf blade and leaf sheath meet) up to 0.5 mm long with tufted hairs on each side

Seedhead

  • 15– 25 cm long and 2–3 cm wide
  • located at the top of the plant
  • brownish purple in colour
  • consists of groups of widely spaced branches that contain many awned seeds
  • produces seeds that can be pollinated

Seed

  • produced in the seedhead and within the lower leaf sheaths at the base of the stem
  • seeds produced in the leaf sheath are self-pollinating
  • yellow-brown in colour
  • 2–3 mm long and 1–1.4 mm wide
  • partially hairy

Habitat

Espartillo thrives in temperate grasslands. It occurs as a weed of roadsides, disturbed areas, open forests, grazing land, native grasslands and waterways. 

Acknowledgements

Written by Rachele Osmond.

Reviewed by Rod Ensbey.

References

Department of the Environment (2011) Weeds in Australia: Amelichloa brachychaeta. Australian Government. Available at: http://www.environment.gov.au/biodiversity/invasive/weeds/ identification/index.html 

Department of the Environment (2011) Weeds in Australia: Amelichloa caudata. Australian Government. Available at: http://www.environment.gov.au/biodiversity/invasive/weeds/ identification/index.html 

Hosking JR, Sainty GR, Jacobs SWL & Dellow JJ (in prep) The Australian WeedBOOK

Parsons, WT and Cuthbertson, EG (2001) Noxious weeds of Australia, CSIRO Publishing, Collingwood.

University of Queensland (2011) Factsheet - Amelichloa caudata, Environmental Weeds of Australia for Biosecurity Queensland.

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Control

Always treat small infestations to prevent them from becoming large ones. Once established, espartillo is very difficult to control. Treating plants before flowering and seed set can be advantageous. Always check the leaf bases for seeds as these can be produced without any visual seed head forming.

In small infestations, clumps can be dug out and removed. Always dispose of the grass in an appropriate manner to prevent further spread. After removal from the site, plants can be dried out and burnt to destroy plant material.

Cultivation

Seedlings are susceptible to cultivation. This needs to occur before new plants start to produce seeds. Winter cropping and repeated cultivation can be effective in cropping situations.

Pasture management

Espartillo is an advantageous grass that can quickly invade rundown and degraded pastures. Avoid heavy and continuous grazing. Light stocking rates and rotational or strip grazing will help to maintain a vigorous and competitive pasture. This may assist in slowing down an invasion of espartillo. Treat individual plants that emerge by manual removal or possible spot spraying.

Herbicide options

Contact your local council weeds officer for control advice for Espartillo - broad kernel (Amelichloa caudata).

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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.
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.
*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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Reviewed 2017