Biological control of cactus weeds of minor importance in South Africa

摘要: Abstract The origin, distribution, weed status and biological control of 13 species alien invasive cacti lesser economic importance in South Africa are reviewed. (The two major cactus weeds, Opuntia aurantiaca Lindley ficus-indica (L.) Miller, is fully reviewed elsewhere.) include the genus Austrocylindropuntia (A. exaltata (Berger) Backeberg A. salmiana (Parmentier));Cereus peruvianus Miller; three Cylindropuntia (Cyl. imbricata (Haworth) Knuth, Cyl. leptocaulis (De Candolle) Knuth rosea Backeberg); Eriocereus martinii (Labouret) Riccobono; five (O. dellenii (Ker-Gawler) Haworth, O. lindheimeri Englemann, spinulifera Salm-Dyck, stricta Haworth vulgaris Miller); and, lastly, Pereskia aculeata Miller. Total success has been achieved biocontrol against using cochineal insects Dactylopius tomentosus (Lamark) ceylonicus (Green), respectively. Introduced insect agents, together with sporadic chemical or mechanical control, have arrested invasion E. (where a pseudococcid Hypogeococcus festerianus (Lizer y Trelles) was agent used), (using D. both cases), opuntiae (Cockerell)). Recognition these as before they became widely distributed much importance, timely initiation coupled locality hot dry areas that enhance debilitating effects on plants, seem to contributed most successes. Relatively isolated, refuge populations weeds escape colonization by imported inimical, but mandatory herbicidal practices often kill natural enemies, main reasons for reduction levels achieved.