Aaron's beard prickly pear (Opuntia leucotricha)

Also known as: Aaron's beard cactus, cacti

Aaron’s beard prickly pear is a cactus with large succulent pads covered in white spines. It can form dense thickets and the spines can injure people and animals.

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How does this weed affect you?

Aaron's beard prickly pear can outcompete native plants, reducing food and habitat for native animals. It has sharp spines up to 5 cm long that:

• cause painful injuries to people, livestock, working dogs and pets
• injure and sometimes kill wildlife that get trapped in the spines
• devalue wool and hides and prevent shearing
• get stuck around the mouth of lambs or calves and prevent them from feeding.

It also forms dense thickets that prevent movement of animals and people. This means that:

• livestock may not be able to access feed 
• mustering is difficult
• access to watering points is reduced
• recreational activities such as bushwalking and camping are restricted.

What does it look like?

Aaron's beard prickly pear is a branched, succulent cactus that grows up to 2.5 m tall and often has a trunk.

Pads (also called stems or cladodes) are:

• light-green to grey-green 
• 16–30 cm long and 12–26 cm wide 
• fleshy and covered in minute hairs
• oval to circular.

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  0.9–2 cm apart
• are brown and woolly
• contain 2–6 spines when young and 10–18 spines when older
• have brown barbed bristles.

Spines are:

• white
• 1.5–4 cm long
• flexible, sometimes curved.

Flowers are:

• yellow, sometimes tinged with red
• 5–7 cm in diameter
• usually on the top section of the pads
• present late spring to summer.

Fruit are:

• pale yellow sometimes pinkish
• barrel-haped
• 2.5–3 cm in diameter
• slightly hairy.

Aaron's beard prickly pear is not known to produce seeds in Australia.

Similar looking plants

Aaron's beard prickly pear looks similar to wheel cactus (Opuntia robusta), which has larger pads and red fruit.

Where is it found?

In NSW, plants have been found in the North West, near Port Macquarie on the North Coast and on the central coast in the Greater Sydney region.

Aaron's beard prickly pear is native to central Mexico. It was introduced into Australia as an ornamental plant.

What type of environment does it grow in?

This cactus grows in arid, semi-arid and warm temperate climates. It grows best on well drained soils.

Maps and records

• Recorded presence of Aaron's beard prickly pear during property inspections (Map: Biosecurity Information System - Weeds, 2017-2023)
  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?

Plant parts

New plants can grow from parts of the stem when they come in contact with the soil. These plant parts can be spread by water, sticking to animals or vehicles and by people dumping garden waste.

 By seed

Aarons beard prickly pear is not known to produce seeds in Australia.

References

Queensland Government (nd) Prohibited invasive plant Aarons beard cactus. Retrieved 9 September 2021 from: https://www.daf.qld.gov.au/__data/assets/pdf_file/0010/1474066/aarons-beard-cactus.pdf

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 9 September 2021 from: https://vicflora.rbg.vic.gov.au/flora/taxon/daef2866-3815-4264-b4a3-3cd7f7ecdfc5

More information

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Control

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

Prevention

To prevent the spread of Aaron's beard prickly pear, do not grow it in gardens or pots. Do not take cuttings of unknown cactus plants to grow out or share with others. 

Stop the spread of cactus into new areas by checking clothing, vehicles and equipment for plant parts before leaving an area that has any cactus weeds.

Disposal

Dispose of Aaron's beard prickly 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 and bristles.

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

Biological control

There are currently no biological control agents available for Aaron's beard prickly pear.

Chemical control

Spray actively growing plants and 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: Follow the label instructions as per Prickly pear (common), smooth tree pear. Thoroughly cover all of the plant with herbicide mix to the point of runoff. Regrowth may occur, so a follow-up application may be necessary. To improve uptake add a paraffinic oil e.g. Uptake®, Titan Paraffin or Apparent Paraffinic spraying 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: Apply as an overall spray, 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: Follow the label instructions as per prickly pear common.To improve uptake add a paraffinic oil e.g. Uptake®, Titan Paraffin or Apparent Paraffinic spraying 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: Follow the label instructions as per common prickly pear (Opuntia spp.). Spray actively growing plants. Thoroughly cover all of the plant.
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. To improve uptake add a paraffinic oil e.g. Uptake®, Titan Paraffin or Apparent Paraffinic spraying 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 2023