Riverina pear (Opuntia elata)

Riverina pear is a cactus up to 2 m tall with orange or yellow flowers. It competes with native plants and forms dense thickets that restrict movement of people and animals.

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How does this weed affect you?

Riverina pear is an invasive cactus that:

• competes with native plants
• reduces food and habitat for native animals
• competes with pasture plants, reducing productivity
• has bristles, and sometimes spines that can injure people and animals.

 It forms dense thickets which:

• reduce access to watering points
• restrict access to feed for livestock and native animals
• make mustering difficult
• restrict recreational activities such as bushwalking and camping.

What does it look like?

Riverina pear is a branched shrub up to 2 m tall. It is usually erect but sometimes scrambles over the ground and climbs over other plants.

Pads (also called stems or cladodes) are:

• glossy green
• 5-25 cm long and 4-9 cm wide
• 2-4 cm thick
• oblong to spoon-shaped.

Cacti pads have bumps on the surface called areoles. Barbed bristles (glochids), spines, leaves, flowers, fruit, roots and new shoots all grow out of the areoles.

Areoles:

• are widely spaced
• have reddish brown barbed bristles
• are usually spineless but some areoles may have 1-3 spines
• are sometimes surrounded by a purplish tinge on the pads.

Spines are:

• a range of colours including red to grey-brown, reddish purple, whitish-yellow or grey
• up to 4.8 cm long
• slightly curved at the tip.

Flowers are:

• 3-4 cm in diameter (occasionally up to 9 cm)
• orange or yellow sometimes tinged red at the end of the petals
• present spring to summer.

Fruit are:

• green ripening to purplish red with greenish pulp
• club or barrel shaped with a sunken end
• 4-6 cm long and 2-2.5 cm in diameter.

Similar looking plants:

Riverina pear looks similar to the following weed species:

• Common pear (Opuntia stricta), which has dull, pale green or grey-green pads.
• Indian fig (Opuntia ficus-indica), which can have much larger pads up to 60 cm long and it’s fruit have barbed bristles.
• Velvet tree pear (Opuntia tomentosa), which has fine, often velvety, hairs on the pads and fruit.

Where is it found?

In NSW, it has been found in the Western, North Western, Riverina, Murray and Greater Sydney regions.  

Riverina pear is a native plant in these South American countries: Argentina, Brazil, Paraguay, Bolivia and Uruguay.

What type of environment does it grow in?

Riverina pear grows in a wide variety of soil types but prefers well drained sandy soils. In its native range plants grow in loams and clay soils. It is drought hardy and grows in regions with more than 150 mm of rain per year. It could grow in most parts of NSW.

Riverina pear is often found growing:

• along the edges of waterways
• in bushland
• in grazing areas
• in disturbed areas such as along roadsides.

Maps and records

• Recorded presence of Riverina pear 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?

By seed

It is not known if the seed is viable in Australia.

Plant parts

New plants can grow from parts of the pads when they come in contact with the soil. Pad fragments can be spread by flood water and by people dumping garden waste. If spines are present the pads can attach to vehicles, equipment or boots.

References

Agüero, J. I., Galati, B. G., & Torretta, J. P. (2018). Structure and ultrastructure of floral nectaries of two Opuntia species (Cactaceae) in relation to their floral visitors. Plant Systematics and Evolution, 304(8), 1057-1067.

Harvey, K.J., McConnachie, A.J. Sullivan, P. Holtkamp, R. & Officer, D. (2021). Biological control of weeds: a practitioner's guide for south east Australia. New South Wales Department of Primary Industries, Orange.

Las Peñas, M. L., Oakley, L., Moreno, N. C., & Bernardello, G. (2017). Taxonomic and cytogenetic studies in Opuntia ser. Armatae (Cactaceae). Botany, 95(2), 101-120.

PlantNET (The NSW Plant Information Network System). Royal Botanic Gardens and Domain Trust, Sydney. Retrieved 14 June 2022 from https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Opuntia~elata

Sheehan, M. R., & Potter, S. (2017). Managing Opuntioid Cacti in Australia: Best Practice Control Manual for Austrocylindropuntia, Cylindropuntia and Opuntia Species. Department of Primary Industries and Regional Development.

VicFlora (2016). Flora of Victoria, Royal Botanic Gardens Victoria, Retrieved 14 June 2022 from: https://vicflora.rbg.vic.gov.au/flora/taxon/935f47cd-008e-43c2-8cd9-39d6ed42a875

More information

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Control

Successful weed control requires follow up after the initial efforts. This means looking for and killing regrowth or new seedlings. Using a combination of control methods is usually more successful.

Prevention

To help prevent the spread of Riverina pear

• Do not grow it in gardens or pots.
• Do not take cuttings of unknown cactus plants to grow out or share with others.
• Avoid driving through areas with cacti.
• If you have been in an area with cacti check boots, equipment, vehicles, caravans, and machinery before leaving the infested area.
• Remove all cactus plant parts using pliers or tongs and dispose of them appropriately.

Disposal

Dispose of Riverina pear by burying it at least one metre deep or by burning in a hot fire. Contact your local council for information about other disposal options. 

Physical control

Dig up small or isolated plants using a mattock or other tools. Wear appropriate protective clothing and gloves to protect against injuries from the spines or bristles.

Larger infestations may be controlled by machinery. Ensure the roots are dug out and that all plant parts are disposed of.

Biological control

Biological control using either of the two species of cochineal in conjunction with the Cactoblastis moth (Cactoblastis cactorum) can control Riverina pear. The two species of cochineal are:

• Dactylopius opuntiae (‘stricta’ and ‘ficus’ lineages)
• Dactylopius ceylonicus

Both of the cochineal insects are available for distribution. There are several species of cochineal that look similar but they each control different species of cactus. It is important to use the correct species of cochineal for each species of cactus. Contact your local weeds officer for information about using cochineal to control Riverina pear.

The cactoblastis moth is widespread and does not need to be redistributed.

Chemical control

Herbicides are especially useful for sparse, scattered infestations. Spray actively growing plants. Cover all parts of the plant with herbicide. Check treated plants and control new growth.

Herbicide options

See Using herbicides for more information.

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Picloram 100 g/L + Triclopyr 300 g/L + Aminopyralid 8 g/L (Grazon Extra®)
Rate: 500 mL per 100 L of water
Comments: Spray actively growing plants, thoroughly cover all of the plant with herbicide mix to the point of runoff. Follow the label instructions as per prickly pear (common). Regrowth may occur, so a follow-up application may be necessary. To improve uptake add a paraffinic oil at the rate of 500 mL per 100 L of water.
Withholding period: Where product is used to control woody weeds in pastures there is a restriction of 12 weeks for use of treated pastures for making hay and silage; using hay or other plant material for compost, mulch or mushroom substrate; or using animal waste from animals grazing on treated pastures for compost, mulching, or spreading on pasture/crops.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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Triclopyr 240 g/L + Picloram 120 g/L (Access™ )
Rate: 1.0 L in 60 L of diesel (or biodiesel such as Biosafe).
Comments: Spray actively growing plants, wetting all areas of the plant to ground level.
Withholding period: Nil
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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Triclopyr 300 g/L + Picloram 100 g/L (Various products)
Rate: 500 mL per 100 L of water
Comments: Spray actively growing plants, thoroughly cover all of the plant. Follow the label instructions as per prickly pear (common). To improve uptake add a paraffinic oil at the rate of 500 mL per 100 L of water.
Withholding period: Nil.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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Triclopyr 600 g/L (Garlon® 600)
Rate: 1.0 L per 75 L of diesel.
Comments: Spray actively growing plants, thoroughly cover all of the plant. Follow the label instructions as per common prickly pear (Opuntia spp.).
Withholding period: Nil.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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Triclopyr 600 g/L (Garlon® 600)
Rate: 3.0 L per 100 L of water
Comments: Spray actively growing plants, thoroughly cover all of the plant to the point of runoff. Follow the label instructions as per common prickly pear (Opuntia spp.) To improve uptake add a paraffinic oil at the rate of 500 mL per 100 L of water.
Withholding period: Nil.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
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	Regional Recommended Measure* (for Regional Priority - Asset Protection) 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 - Asset Protection) 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.
Hunter	Regional Recommended Measure* (for Regional Priority - Asset Protection) 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.
Murray	Regional Recommended Measure* (for Regional Priority - Containment) Whole of region: 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.
Western	Regional Recommended Measure* (for Regional Priority - Asset Protection) 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.
	*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 2024