Although many species of aphids are of the greatest economic importance, only little is known about the aphid fauna of the Union of South Africa. Theobald has descriptionbed or mentioned in his papers on African Aphididae a number of species which were collected in South Africa. More recent papers on African Aphididae deal, however, with collections made in other parts of the continent. Mimeur, for example, studied the aphids of Morocco, and Hall listed species occurring in Egypt and Southern Rhodesia. East African aphids are the subject of several publications by de Lotto and by Eastop. Other puplications dealing with new or little known African aphids are few in number.
The genus Stipsostoma is one of several which comprise the tribe Eurychorini. The genus was previously represented by only two species: S. sculpta (Gebien, 1920), descriptionbed from the coastal peneplane of South West Africa, north of the Orange River mouth, and S. holgatensis Koch, 1952 from the Richtersveld south of the Orange River mouth. A third, new species, is descriptionbed below.
At the beginning of April 1958 a heavy infestation of Plusia orichalcea Fabr. was observed in an experimental potato planting near Pretoria. Some of these potatoes had been sprayed regularly with Systox, Metasystox and lsochlorothion in insecticidal trials for the control of the spread of aphid-transmitted virus diseases. There were conspicuous differences in the degree of P. orichalcea infestations in the different insecticidal treatments: the plots sprayed with Systox and Metasystox were heavily infested, while the unsprayed controls carried only a light infestation, and the plots sprayed with Isochlorothion were not attacked at all.