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The Uitenhage Biological Control Facility

The BCRG took over this facility outside Uitenhage in April 2015, after the success of the Waainek facility in Grahamstown. The Uitenhage facility focuses on the rearing of agents for alien invasive cacti, which are serious environmental and agricultural weeds throughout South Africa. Biological control of cacti has been very successful in both South Africa and Australia. The very first biological control agent introduced into South Africa was a cochineal insect which targeted the drooping prickly pear (Opunita monocantha) over 100 years ago. Drooping prickly pear was a major problem in the Eastern Cape Province at that time, covering large areas of bush and grazing land in high densities. After the release of the cochineal insect there was a dramatic decline in drooping prickly pear populations and it is no longer considered a problem. At present, six species of agents are being mass-reared on six cactus weeds at the Uitenhage facility (see table below). All but one (Pereskia stem-wilter) of the agents are types or species of cochineal. Cochineal insects are a genus of scale insects which feed only on cacti in the genus Opuntia. The most familiar stage of the cochineal insect’s life-cycle is the sedentary adult phase where white fluff covers the insect, protecting it from predators and parasites. Each different cochineal species specialises in feeding on one particular weed species so it is essential that the correct type of cochineal is used to control the correct weed.

A team of nine people are employed to mass rear and release these agents. Farmers, conservationists and landowners make requests and the agents are provided free of charge. The team is also involved in monitoring how effective the releases are in controlling the weeds. If you have a problem with invasive cacti please contact the BCRG and we will advise on the best way of controlling that species and provide you with control agents if appropriate.  The Uitenhage manager, Ruth Scholtz, can be contacted on scholtzruth4@gmail.com 

The table below lists the biological control agents that are mass reared for Cacti weeds:

Invasive Plant
Biological Control Agent
Opuntia aurantiaca (Jointed cactus)
 Jointed cactus cochineal (Dactylopius austrinus)
Cylindropuntia imbricata (Ibricated cactus)
Imbricata cochineal (Dactylopius tomentosus "imbricata type")
Opuntia monacantha (Drooping prickly pear)
Monacantha cochineal (Dactylopius ceylonicus)
Opuntia stricta (Australian pest pear)
Stricta cochineal (Dactylopius opuntiae "stricta type")
Harrisia martinii 
Queen of the nigh mealy bug (Hypogeococcus festerianus)
Pereskia aculeata (Pereskia)
 Pereskia stem-wilter (Catorhintha schaffneri


Last Modified: Wed, 26 Oct 2016 16:34:44 SAST