INSECT HERBIVORES ASSOCIATED WITH INDIGENOUS SPECIES OF SOLANUM (SOLANACEAE) IN THE TRANSVAAL, SOUTH-AFRICA, AND IN NAMIBIA

Several indigenous Solanum (Solanaceae) species were surveyed in the T ransvaal and Namibia as part of a broader study of the insect herbivor es associated with indigenous, as well as weedy and cultivated exotic, solanums in southern Africa. Insects were collected on three Solanum species in the Transvaal and on 10 in Namibia. Solanum panduriforme E. Mey. and S. incanum L. were abundant in both regions, while S. capens e L. was the most common species in Namibia. These three Solanum speci es supported an abundance of insect herbivores, which included marry o ligophages found on solanums in other regions of South Africa. Most of the Solanum insect species were found on a wide range of host plants, in a variety of habitats and under various climatic conditions. The e xtensive oligophagy among indigenous solanaceous insects has implicati ons for introduced Solanum species and these are discussed. Although i ndigenous solanaceous insect species readily develop on the introduced crop S. melongena L. (eggplant), none attack the exotic weeds S. elae agnifolium Cav. and S. sisymbriifolium Lam., except superficially. The taxonomic relationships between the introduced and indigenous Solanum species may account for these discrepancies. The surveys further emph asize the need to introduce natural enemies into South Africa for biol ogical control of exotic Solanum weeds.