Opuntia engelmannii (Engelmann's prickly pear, Calico cactus)

[= Opuntia tardospina, Opuntia lindheimeri]

Life > eukaryotes > Archaeoplastida > Chloroplastida > Charophyta > Streptophytina > Plantae (land plants) > Tracheophyta (vascular plants) > Euphyllophyta > Lignophyta (woody plants) > Spermatophyta (seed plants) > Angiospermae (flowering plants) > Core Eudicots > Order: Caryophyllales > Familty: Cactaceae > Genus: Opuntia

Native to southern USA. Opuntia engelmannii var. lindheimeri (Texas prickly pear) is a declared Category 1 invasive plant in South Africa (listed as Opuntia lindheimeri).

Ecological interactions in southern Africa

Herbivores

• Cactoblastis cactorum (Lepidoptera: Pyralidae: Phycitinae). The orange and black striped larvae eat a wide variety of Opuntia species, including Opuntia engelmannii, causing extensive damage to the latter host plant. Cactoblastis cactorum was originally introduced to South Africa in 1933 for the biological control of Opuntia ficus-indica and in 1938 it was released against Opuntia engelmannii infestations (Klein 2011).

• Dactylopius opuntiae (Hemiptera: Dactylopiidae). The 'ficus' biotype was released in 1938 against Opuntia ficus-indica but it was also released against Opuntia engelmannii, causing considerable damage (Klein 2011). Dactylopius species are collectively known as cochineal insects and are all characterised by having vivid red body contents that from Dactylopius coccus is used for producing cochineal dye. The females suck the juices from the cactus and those of Dactylopius opuntiae are easily noticed on the plant because of their untidy covering of waxy filaments, looking rather like blobs of cotton wool.

Publications

• Klein H. 2011. A catalogue of the insects, mites and pathogens that have been used or rejected, or are under consideration, for the biological control of invasive alien plants in South Africa. African Entomology 19(2): 515-549.

Text by Hamish Robertson