Opuntia stricta (shrub)

Ecology Distribution Management Info Impact Info References and Links Contacts

Taxonomic name: Opuntia stricta (Haw.) Haw. Synonyms: Cactus opuntia L. var. inermis DC., Cactus strictus Haw., Opuntia airampo Phil., Opuntia anahuacensis  Griffiths, Opuntia atrocapensis Small, Opuntia bartramii Raf., Opuntia bentonii Griffiths, Opuntia cyanella Griffiths, Opuntia dillenii  (KerGawl.) Haw., Opuntia gilvoalba Griffiths, Opuntia gomei  Griffiths, Opuntia horrida Salm-Dyck ex DC., Opuntia humilis (Haw.) Haw., Opuntia inermis (DC.) DC., Opuntia keyensis Britton ex Small, Opuntia laxiflora Griffiths, Opuntia longiclada  Griffiths, Opuntia macrarthra Gibbes, Opuntia magnifica Small, Opuntia maritima Raf., Opuntia nitens Small, Opuntia parva A.Berger, Opuntia spinalba Raf., Opuntia stricta (Haw.) Haw. var. dillenii (KerGawl.) L.D.Benson, Opuntia tenuiflora Small, Opuntia tunoides Gibbes, Opuntia zebrina Small Common names: Araluen pear, Australian pest pear (English), chumbera (Spanish), common pest pear (English), common prickly pear (English), erect prickly pear (English), Feigenkaktus (German), gayndah pear, nopal estricto (Spanish), pest pear of Australia (English), sour prickly pear (English), spiny pest pear (English), suurturksvy Organism type: shrub Opuntia stricta is a cactus that can grow up to 2 metres in height and originates in central America. This spiny shrub favours habitats such as rocky slopes, river banks and urban areas. Opuntia stricta was considered to be Australia's worst ever weed. Opuntia stricta is also invasive in South Africa, where biological options are currently being explored to control the problem. Description “Spreading to an erect shrub to 2 metres. Basal stem-segments sometimes thickened, trunk-forming; uppersegmets elliptic to obovate, 10-35cm long, 7-20cm wide, glabrous, dull green to grey-green. Leaves conical, 4.5-6mm long. Spines up to 11 per areole, 1-6cm long, yellow to brown; glochids yellow. Flowers 5-6.5cm diam.; petaloid lobes spreading, yellow. Fruit obovoid with depressed apex, 4-6cm long, 2.5-4cm diam., purple. Seeds 4-5mm long, pale brown.” (George, 1984, In PIER, 2003) Similar Species Opuntia ficus-indica More Occurs in: agricultural areas, ruderal/disturbed, scrub/shrublands, tundra, urban areas, water courses Habitat description Originally garden plants or used for fencing, they may occur close to old buildings, but can also be spread far from habitation, (ESC). Rocky slopes and river banks are favoured habitats, (ESC). General impacts Dense infestations can impede movement, (ESC). Prickly pears can dominate the vegetation of rocky outcrops displacing native species, some of which may be restricted to such outcrops, and consequently be relatively rare, (ESC). Opuntia stricta (Haworth) has invaded and formed dense infestations over large areas of the Kruger National Park in South Africa, (SANP). It was considered to be Australias worst ever weed burying approximately 24 million ha of Queensland under a mat up to 2 metres deep. Uses Cultivated for Medicinal/culinary uses in some areas, (Thomas & Randall, 2001). Geographical range Native range: “Tropical and subtropical coast of eastern North America, Bermuda, West Indies and adjacent South America” (George, 1984, In PIER, 2003) Introduced In: New Caledonia, Solomon Islands, Australia, South Africa, Yemen, Eritrea, Ethiopia and Somalia. Introduction pathways to new locations Agriculture: This plant came to Australia on the first fleet, making it the oldest weed. Early settlers in Australia planted O. stricta for ornamental purposes and as hedges to keep cattle under control before barbed wire became affordable. (Australian Plants online, 1999) Local dispersal methods Garden escape/garden waste: Other (local): The segments will take root from the "eyes" if left in contact with the ground, (ESC). Water currents: They can be moved in floods leading to infestations along river banks, (ESC). Management information Physical: "Plants can be dug out, but need to be disposed of very carefully because of their ability to take root again if left on the ground. Segments will remain viable even if hung up in vegetation or placed on rocks away from soil, and they may be relocated onto soil by wind, water or animals. Deep burial or burning is safest, although a lot of wood is required to consume the succulent stems. Be very careful when handling any prickly pears, as the spines easily get into the flesh and break off, causing irritation. Wear leather gloves and thick clothing and shoes. Kitchen tongs are useful for handling the smaller tiger pear segments." (ESC) Chemical: "Spraying with woody weed specific herbicide can be effective, but a high concentration is needed." (ESC) Biological: "The biological control of prickly pear, largely by the introduction of the Phycitid moth Cactoblastis cactur Berg from Argentina, is one of the most spectacular successes of economic entomology" (George, 1984. In PIER, 2003). Opuntia stricta is also controlled by a cochineal insect, Dactylopius opuntiae, (PIER, 2003). "Biological controls (the Cactoblastis moth, or cochineal insects) are effective in warmer climates, but in southern areas they need to be reintroduced after winter. They may weaken plants and prevent seeding, but will not eradicate infestations." (ESC) A Risk assessment of Opuntia stricta for Australia was prepared by Pacific Island Ecosystems at Risk (PIER) using the Australian risk assessment system (Pheloung, 1995). The result is a score of 20 and a recommendation of: reject the plant for import (Australia) or species likely to be a pest (Pacific). Reproduction Seed, (PIER, 2003). The segments will take root from the "eyes" if left in contact with the ground, and because they are so succulent, they remain capable of rooting for several months after being detached from the parent plant, (ESC). They can be moved in floods leading to infestations along river banks, (ESC). This species has been nominated as among 100 of the "World's Worst" invaders Reviewed by: Major update under progress Dr. Vila Montserrat. Centre de Recerca Ecologica I Aplicacions Forestals, Universitat Autonoma de Barcelona. Spain Principal sources: Pacific Islands Ecosystems at Risk, (PIER) Compiled by: IUCN/SSC Invasive Species Specialist Group (ISSG) To contribute information, please contact Shyama Pagad. Last Modified: Monday, 28 November 2005