Prof HO de Waal, researcher in the Department of Animal, Wildlife and Grassland Sciences at the University of the Free State (UFS), has developed a standard procedure for the processing of spiny cactus pear (Opuntia spp.) into livestock fodder. This will ultimately assist in the management of massive infestations of spiny cactus pear and help to convert underutilised farmland back to natural grazing land.

In addition to applying biological control agents, mechanical control is used to harvest alien spiny cactus pear, and the large volume of material is processed as livestock feed.

Introduced to South Africa

Three hundred years ago, seafarers visiting the Cape of Good Hope introduced the well-known invading alien spiny cactus pear to South Africa. These were later transported inland and by the 1950s about one million ha of South Africa had been invaded by the alien cacti.

Some regions in the Eastern Cape have been taken over by dense, impenetrable thickets of these cacti. Invasive alien plants (IAPs) such as cacti pose a direct threat to, among others, South Africa’s water security and productive use of land.

A range of methods is used to control IAPs, including mechanical, chemical, biological, and integrated control methods.

A control programme must include the three phases of initial control to drastically reduce the existing population; follow-up control of seedlings, root suckers, and coppice growth; and maintenance control on an annual basis to sustain low alien plant numbers.

Processing spiny cactus pears

According to Prof De Waal, the harvesting and processing of the spiny cactus pear is fairly simple. Although it requires a good measure of physical strength, perseverance, and the necessary protective clothing, the cacti can be processed by harvesting the plants; shredding the cladodes through a cladode cutter; then drying them in the sun, and lastly grinding it in a hammer mill. “The long spines are degraded mechanically by grinding the sun-dried cladode strips in a hammer mill before including it in balanced livestock diets,” said Prof De Waal.

Infestations will be opened, reclaimed, rehabilitated and the natural pastures (veld) allowed to revert back to grazing for livestock.

The National Resource Management Programme (NRM)P) will be approached for official support in clearing and rehabilitating massive areas of infestation by alien spiny cactus pear in the Eastern Cape. Such financial support will be an investment in reducing the infestation by invaders and the rehabilitation and sustainable use of natural resources in South Africa.