Quick Facts

Quick facts

• White-spined Prickly Pear (Opuntia streptracanta) is an invasive weed that can take over pastoral and agricultural lands.
• Stem segments fragment and immature fruits can be distributed by animals, vehicles and by water.
• Fruits are succulent and are eaten by birds and animals and seed is distributed in their droppings.
• It can cause injury to people and animals.
• If this species is seen please notify your local weed management authority.

What Does It Look Like?

What is it?

White-spined Prickly Pear (Opuntia streptacantha) is a shrub or tree-like shrub to 4 m tall, branching from the base or forming a trunk 15–40 cm diameter. The dark green stem segments are obovate (egg-shaped in outline) or almost round, glabrous (lack hairs), 20–48 cm long and 14–30 cm broad. The areoles (spots on stem segments and fruits that contain the spines and glochids) have usually 3–9 but up to 20 pale yellow to dark grey spines to 2.5 cm long and numerous short yellow to red-brown glochids (clusters of small barbed bristles).

The flowers are 5–12 cm diameter and the petaloid lobes are spreading, yellow to orange, the outer segments reddish.

The dull red, purple or occasionally yellow fruits are egg-shaped to globose, 5–8 cm long and 3–5 cm diameter. The apex of the fruit is flattened or slightly depressed (Telford 1984; Harden 1990; Anderson 2001).

For further information and assistance with identification of White-spined Prickly Pear contact the herbarium in your state or territory.

Flower colour

Yellow

Growth form (weed type/habit)

Tree, Shrub

Where it currently grows? Preferred habitat

In Queensland White-spined Prickly Pear is common in Eucalyptus woodlands and on river flats or river banks. It has also been reported from previously cleared areas in Brigalow (Acacia harpophylla) regrowth areas (Queensland Herbarium records). In Victoria and South Australia it occurs in open Eucalyptus woodlands in usually in association with various chenopods.

Are there similar species?

White-spined Prickly Pear can be confused with other Prickly Pear species.

Common Prickly Pear (Opuntia stricta) is a much lower growing shrub, rarely more than a metre tall. Its stem segments are oblong, elliptic to obovate, mid to pale green with a whitish waxy coating and also lack hairs. Fruits are almost rounded to pear-shaped and have very scattered areoles with prominent tufts of glochids (Chinnock pers. comm. 2007).

Velvet Tree-pear (Opuntia tomentosa) is a shrub or small tree to 7 m tall. Its stem segments are elongated, oblong or elliptic, covered with a fine velvety pubescence. The flowers are distinctive, orange but the outer smaller perianth segments are purplish (Chinnock pers. comm. 2007).

Wheel Cactus (Opuntia robusta) is usually a shorter shrub which also has almost circular stem segments that are bluish green and lack hairs. The fruits are bluish green, 6–8 cm long, 5–6 cm diameter. This species is not known to occur in areas inhabited by White-spined Prickly Pear (Chinnock 2007, pers. comm.).

Why Is It A Weed?

What are its impacts?

The impacts of White-spined Prickly Pear are similar to those of the other Opuntia species.

Agriculture: Dense infestations can impede movement and lay waste to agricultural and pastoral lands, provide harbour for feral animals and crowd out native plant species. However, it is not currently considered a major threat to agriculture in Australia (Cunningham et al. 2003).

Human impacts: The spines and glochids can cause injury to humans and animals (Chinnock 2007 pers. comm.). 

How does it spread?

White-spined Prickly Pear will reproduce from stem segments or immature fruits which readily root when in contact with soil. The succulent fruits are attractive to birds and animals and the seeds are carried in their droppings. Stem segments can be distributed long distances during flooding. Discarded plants and movement of plant parts during disposal can also lead to new outbreaks (Land Protection 2006).

What is its history in Australia?

White-spined Prickly Pear was first planted at Gracemere near Rockhampton in 1880 (Hosking et al. 1988).

How To Manage It?

Best practice management

Non-chemical control: Mechanical control using machinery is difficult because Prickly Pear pads can easily re-establish.

Fire: A hot fire is an effective control method for dense Prickly Pear infestations (Land Protection 2006).

Biological control: White-spined Prickly Pear has been recognised as a target for biological control through a cross-jurisdictional government process. This allows activities to be undertaken to develop effective biological controls. Cactoblastis insect (Cactoblastis cactorum) is known to attack this species but only causes minor damage. The Cochineal insect (Dactylopius opuntiae) is more damaging and occurs widely on this species. It is the main biological control used for this species and Velvet Tree Pear. This insect can be spread manually by placing a few affected pads on unaffected plants (Hosking et al. 1988; Land Protection 2006)

Chemical control: A number of herbicides are also effective by spraying or injecting (Land Protection 2006).

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au

Does it have a biological control agent?

YES

When does it grow? (lifecycle/growth calendar)

Little specific information on the lifecycle of White-spined Prickly Pear is currently available. Plants reproduce from stem segment fragments, immature fruit or by seed. It is drought tolerant and can remain vigorous during hot dry periods producing flowers and fruit (Chinnock 2007 pers. comm.).

Where Is It Found?

Which states and territories is it found?

NSW, QLD, SA, VIC

What areas within states and territories is it found?

White-spined Prickly Pear occurs in areas of central Queensland east of the Dawson Range from the Mackenzie river north of Dingo to near Wandoan, and to Gracemere and Biloela in the east. It occurs in the extreme northern part of New South Wales (Hosking et al. 1988; Harden 1990). It also known from a small area in north western Victoria and a few locations in the Murray region of South Australia.

Where does it originate?

White-spined Prickly Pear is widespread and common in various states of central Mexico (Anderson 2001).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NSW, NT, QLD, SA, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Opuntia streptacantha

Other scientific names (synonyms)?

Does it have other known common name(s)?

White-spined Pear, Cardona Pear, Gracemere Pear, Westwood