Common pear (Opuntia stricta)

Also known as: common prickly pear, prickly pear, common pest pear, cactus, cacti

Common pear is a cactus up to 2 m tall with yellow flowers and purplish red fruit. It forms dense infestations, which outcompete pasture grasses and native plants and restrict movement of people and animals.

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How does this weed affect you?

Common pear can outcompete other plants and form dense infestations. It:

• restricts the movement of animals and people
• reduces productivity by outcompeting pasture plants and reducing access to feed
• makes mustering difficult
• reduces access to watering points
• outcompetes native plants
• reduces food and habitat for native animals
• makes recreational activities such as bushwalking difficult.

Common pear sometimes has spines that can:

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

Common pear is also a host plant for fruit flies and provides harbour for pests including foxes and rabbits.

What does it look like?

Common pear is an upright, spreading cactus usually less than 1.5 m tall but occasionally up to 2 m. The leaves are reduced to scales 3–4 mm long and they drop off when plants are young.

There are two varieties (var.) in NSW:

• var. stricta is more common across NSW
• var. dillenii occurs only in the far north-west and south-east of the state.

 Pads (also called stems or cladodes) are:

• dull bluish or greyish-green to green
• fleshy
• 10–30 cm long, 7–20 cm wide and up to 2 cm thick
• egg-shaped
• segmented and flattened.

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

Spines are:

• 1–5 cm long
• yellow
• often absent or in clusters of 1–2 per areole for var. stricta
• in clusters of up to 11 for var. delleni.

Bristles are:

• brownish and woolly
• short and barbed.

Flowers are:

• lemon yellow with greenish or pink markings on the back of the petals
• 5–8 cm in diameter.

Fruit are:

• green when immature
• reddish-purple with a white waxy covering when mature
• 4–5 cm long and 2.5–4.0 cm wide
• almost round to pear-shaped with a flattened top
• with scattered tufts of hairy bristles.

Seeds are:

• yellow to pale brown
• round
• 4–5 mm in diameter.

Roots:

Roots are shallow and fibrous.

Similar looking plants

Common pear looks similar to:

• Indian fig (Opuntia ficus-indica), which can grow taller and often has a trunk. It has larger pads (30–50 cm long) and flowers (7–10 cm).
• Velvet tree pear (Opuntia tomentosa), which is often taller (up to 5 m) with larger pads and fine hairs on the pads and fruit that give it a velvety appearance. The flowers are orange-red.
• Smooth tree pear (Opuntia monacantha), which is taller and has shiny dark-green, elongated, thinner pads, that often droop down.

Where is it found?

In NSW, common pear is mostly found in the North West, Central West and Hunter regions. However it has been present across all regions in NSW. It was introduced to NSW in the 1830s. In the early 1900s, it had invaded 25,000,000 hectares of northern NSW and Queensland.

 It is native to southeastern parts of North America, the east coast of Mexico, northern South America, Cuba, Bahamas and Bermuda.

What type of environment does it grow in?

Common pear can grow in tropical, subtropical, warm temperate and semi-arid climates. It tolerates full sun and shade. It grows in a wide range of soil types including saline soils, sand, loams and heavy clays. It can grow:

• in grasslands, woodlands shrublands and forests
• on steep, rocky slopes
• on beaches
• in disturbed areas such as roadsides
• on agricultural land.

Maps and records

• Recorded presence of Common 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?

By seed

Common pear produces an average of 110 seeds per fruit and the seeds can remain viable for up to 15 years. Fruit are eaten by birds, foxes and other animals and seeds are spread in their droppings.

By plant parts

Common pear can regrow from stem fragments, flowers and immature fruits. Stem segments can be spread by animals, vehicles, water or wind and quickly take root. Dumping of unwanted plants causes new outbreaks.

References

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.

Parsons, W.T. and Cuthbertson, E.G. (2001). Noxious Weeds of Australia. Inkata Press, Melbourne.

PlantNET (The NSW Plant Information Network System). Royal Botanic Gardens and Domain Trust, Sydney. Retrieved 19 November 2021 from: https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Opuntia~stricta

Reyes-Agüero, J. A., & Valiente-Banuet, A. (2006). Reproductive biology of Opuntia: A review. Journal of arid environments, 64(4), 549-585.

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.

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 seedlings. Using a combination of control methods is usually more successful.

To manage common pear:

• control all plants in new or scattered infestations rather than wait for biological control agents
• for large infestations release populations of the cochineal bug D. opuntiae ‘stricta’ lineage.

Prevention

To help prevent the spread of common 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 under 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 common pear plant parts by burying at least one metre deep or 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 spines or bristles.

Dense infestations or large isolated plants can be removed with machinery where there is good access to the site, the site is not environmentally sensitive and plant parts can be safely disposed of. Ensure the roots are dug out and that all plant parts are disposed of.

Biological control

There are two successful biological control agents for common pear:

• cactoblastis moth, (Cactoblastis cactorum)
• cochineal bug (Dactylopius opuntiae ‘stricta’ lineage).

In the early 1900 the infestations of common pear were so bad that many farms had been abandoned. The cochineal bug was released in 1921 and had some impact. The cactoblastis moth was released in Australia in 1926. By 1932 it had successfully controlled common pear on 25 million ha of land in New South Wales and Queensland and the controlled land was able to be farmed again. 

The cactoblastis moth is now widespread and does not need to be redistributed. To help attract the moths to a site, cut and stack the pads in a pile about 2m x 2m and 1 m high in spring or summer. The moths will multiply quickly in the stack. . Heavy rain or cold weather will slow down control by the moth, so it is best to make the stacks and transfer the infested cladodes in spring or summer. Avoid transferring the moths when there is likely to be heavy rainfall.

The cochineal bug is suitable for redistribution and in many areas control can be faster if cochineal bugs are used as well as moths. The cochineal bug gives better control than the cactoblastis moth in cool regions of NSW and in hot dry regions where the pads dry out.

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

Chemical control

Spot spraying

Herbicides are especially useful for sparse, scattered infestations. Spray actively growing plants. Cover all parts of the plant with herbicide to the point of visible wetness. 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 in 100 L of water
Comments: Spray actively growing plants. 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. See label for information about using biodiesel.
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 in 100 L of water
Comments: Spot spray application. Spray actively growing plants. 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: 800 mL in 60 L of diesel
Comments: 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 in 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