Pest pear of Australia
Common name:Pest pear of Australia
Scientific name:Opuntia stricta
Alternative common names:
Common prickly pear, coastal prickly pear, common pest pear, erect prickly pear, pest prickly pear, prickly pear, sour prickly pear, southern spineless cactus.
Pest pear of Australia is an upright (erect) or spreading fleshy shrub usually growing 50-100cm tall, but occasionally reaching 2m in height. The species is known to invade rocky slopes and river banks as well as degraded areas in grasslands and woodlands.
Where does this species come from?Caribbean region.
What is its invasive status in South Africa?NEMBA Category 1b.
Where in South Africa is it a problem?Kruger National Park.
How does it spread?This plant reproduces by seed and vegetative reproduction via its fleshy cladodes, which become dislodged from the plant and produce roots. Cladodes are spread by attaching to animals, footwear and vehicles. They may also be dispersed by flood water and in dumped garden waste. The fruit is eaten by various animals (birds and rodents) and the seeds then spread in their droppings.
Why is it a problem?Pest pear of Australia is a very serious problem in arid lands. It is an irritant due to its spines and glochids (barbed hairs or bristles). People have abandoned homes/villages as a result of this weed. It prevents access, displaces indigenous species and causes injuries to people, livestock and wild animals. Pastoralists claim that excessive consumption of fruit by livestock causes death - some pastoralists say they have lost all of their livestock.
What does it look like?Leaves: The leaves are reduced to tiny cylindrical or conical structures (4.5-6mm long) and are quickly shed from the developing cladodes (leaf-like branches). Flowers: The flowers (up to 7cm long and 6-8cm across) are bright yellow, but often have pink or red markings on the outer 'petals' (most of these are actually petal-like structures known as petaloids). They are borne singly on fleshy bases along the margins of the cladodes. Each flower has numerous petaloids and stamens. Fruit: The immature fruit is green, but turns reddish-purple as it matures. These berries (4-8cm long and 2.5-4cm wide) are fleshy (succulent), egg-shaped and usually have slightly depressed tips. Each fruit has several tufts of glochids on its surface. Seeds: The red or purple pulp in the centre of the fruit contains many seeds. These seeds (4-5mm long and 4-4.5mm wide) are generally yellow or pale brown and somewhat rounded (subglobular) in shape.
Does the plant have any uses?It is used as a barrier fence and in some parts of the world as livestock fodder.