The phytophagous insects and mites of cultivated plants in South Africa: patterns and pest status.
In South Africa, 472 species of phytophagous insects and mites on 121 species of crop and ornamental plants there were evaluated according to their pest status, which was determined by a method developed for the purpose and which is described. An analysis by taxon showed that Lepidoptera, Homoptera (Aphididae, Diaspididae, Pseudococcidae, Coccidae, Margarodidae and Cicadellidae) and Coleoptera together accounted for 75% of all pest problems in South Africa; 88 families in 11 orders are listed and ranked by pest status, as are the 101 most important pest species. The pest status of indigenous and exotic insects and mites on indigenous and introduced food-plants is summarised. Sap-sucking species were shown to be somewhat more important than chewing species; borers were of a lower order of importance and gall-formers and miners were of relatively little significance as pest. The various guilds of phytophagous species were analysed on the basis of their feeding habits and the damage they cause to their food-plants. On the basis of mean pest status per species, those transmitting plant diseases were the most important guild. Trees and perennial shrubs harboured predominantly sap-sucking species and fewer chewing and boring species. All flowers, vegetables, crops and grasses, however, were attacked mostly by chewing species and harboured predominantly fewer sap-sucking species and very few borers.