Biological control of pest cactus and cactus pests in Africa

The cactus, Opuntia ficus-indica Mill. has become an increasingly important crop in some arid parts of Africa, particularly the Mediterranean region of North Africa.
The cochineal insect Dactylopius opuntiae (Cockrell) has become a serious pest of this crop.
In the Mediterranean region, biocontrol, using predators of the cochineal insect, is an important component of control strategies.
The use of natural enemies to control pest cochineal in Ethiopia (East Africa) is also being considered.
Many cacti species are however serious agricultural pests themselves, and biocontrol of Opuntia and Cylindropuntia species is implemented in many countries in Africa, including Kenya and South Africa, using host specific cochineal insects as agents.
These biocontrol agents have dramatically reduced populations of several pest cactus species, and keep these populations at low levels, with significant benefits to livelihoods and indigenous biodiversity.
The agents used for the control of pest cochineals, are not host specific to a single cochineal species, and would therefore also feed on biocontrol agent cochineal insects and reduce their efficacy.
Agents released in the Mediterranean region of Africa are unlikely to disperse to sub-Saharan Africa, but if they are released in Ethiopia they are likely to spread throughout the African continent and may disrupt the biological control of cactus weeds, resulting in negative impacts to farmers and ecosystems on the continent.
The use of augmentative biocontrol using cochineal predators that are already present in sub-Saharan Africa, rather than importing new agents from the native distribution, would mitigate this conflict of interests.

X International Congress on Cactus Pear and Cochineal: Cactus – the New Green Revolution in Drylands

I. Paterson, A. Witt

biocontrol of weeds, cactus control, conflict of interest, Cryptolaemus montrouzieri, Opuntia ficus-indica

https://doi.org/10.17660/ActaHortic.2022.1343.71