​Boxing-glove cactus (Cylindropuntia fulgida var. mamillata forma monstrosa) (Cactaceae)


The Weed

The name boxing-glove cactus applies only to the crested morph (forma monstrosa) of Cylindropuntia fulgida var. mamillata), which is the most common form of Cyl. fulgida var. mamillata that occurs in South Africa. Boxing-glove cactus is native to south-central Arizona in the USA, from where it was probably imported into South Africa by succulent collectors as an ornamental. It has invaded the arid regions of the Northern and Eastern Cape as well as the Limpopo Provinces of South Africa, in addition to the southern part of Namibia and several parts of Australia.

Although it belongs to the same species as chain-fruit cholla (Cyl. fulgida var. fulgida), boxing-glove cactus differs entirely in appearance. Boxing-glove cactus is a grey-green shrub, approximately 1-1.5 m tall. Plants can consist of varying proportions of cylindrical to club-shaped stem segments, flattened and twisted segments that frequently resemble boxing gloves, and small, loosely attached terminal segments. The stem segments are corrugated (tuberculate) and appear almost spineless, especially in older, crested stems. However, sparse, short spines without barbs and with tightly fitting sheaths are, in fact, present. Occasionally a part of a boxing-glove cactus plant is covered with the typical long, dense spines that are characteristic of chain-fruit cholla. Flowers, which are not often seen, have magenta, backwards-curving "petals", just like chain-fruit cholla. Boxing-glove cactus also produces its fruit in chains but, in contrast with the smooth fruit of chain-fruit cholla, its fruit have distinct tubercles. Like chain-fruit cholla, its fruit are also sterile.

Vegetative reproduction is the most important means of dispersal for boxing-glove cactus in this country.  The terminal segments constantly become dislodged, and either take root around the mother plant to form dense thickets, or are dispersed by animals or flood water before rooting.  Boxing-glove cactus injures human beings and animals and drastically reduces the carrying capacity of affected land.  Cylindropuntia fulgida (which includes boxing-glove cactus) is listed as a category 1b invasive plant in terms of the Alien and Invasive Species Regulations (AIS), National Environmental Management: Biodiversity Act (Act No 10 of 2004) . Land owners are therefore obliged to control it effectively, or to re​move and destroy it if possible. No trade or planting is allowed.​

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Control

No herbicides have been registered in South Africa to control boxing-glove cactus, and manual or mechanical control is not feasible, due to the numerous easily-detachable stem segments that drop off the plant and grow into new plants.

Biological control of boxing-glove cactus is, however, extremely effective. The 'cholla' biotype of the cochineal insect, Dactylopius tomentosus, which was introduced to control chain-fruit cholla, is exceptionally damaging to both of these varieties of Cyl. fulgida. Dense infestations of boxing-glove cactus in the vicinity of Upington and Askham (Northern Cape) have been devastated in a surprisingly short period of time by this biocontrol agent. In certain areas, the cactus moth, Cactoblastis cactorum is highly damaging to the plant.

More information

The biological control project against chain-fruit cholla (using the same cochineal as for boxing-glove cactus) is discussed in a 2011 review.pdf 

Contact Hildegard Klein, E-mail: KleinH@arc.agric.za.