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Three field trials were conducted at Namulonge Agricultural and Animal Production Research Institute to investigate the population dynamics of Bemisia tabaci Gennadius and its associated aphelinid parasitoids in Uganda. Results showed that more whitefly occurred on the cassava mosaic disease-resistant variety, (Nase 4) compared to the susceptible variety, (Ebwanatereka). Two species of aphelinid parasitoids, Eretmocerus mundus Mercet and Encarsia sophia Girault and Dodd, were identified during the study. Overall percent parasitism did not differ significantly ( P >0.05) between varieties in all the trials, but significant differences occurred at 13, 15 and 21 weeks after planting during late season (2000), 18 weeks after planting during early season (2001), and 8 weeks after planting during late season (2001). The trends in the build up in numbers of both parasitoids species and apparent parasitism were similar, differed significantly on certain dates. It was, however, noted that percent parasitism decreased with nymph number. The significance of this phenomenon on the potential use of these aphelinid parasitoids as biocontrol agents of the cassava whitefly is discussed. [ABSTRACT FROM AUTHOR]

Wild and cultivated plants in the vicinity of Kibbutz Nahshon and a few additional locations in Israel were sampled for the presence of Bemisia tabaci Genna-dius (Homoptera: Aleyrodidae). The whiteflies, together with their parasites, Eretmocerus mundus and Encarsia lutea, were found to develop on numerous host species throughout the winter. Especially high levels were reached on Lan-tana camara, Abutilon grandifolium and Ipomoea batatas. During late winter and spring the population on these hosts declined. From April onwards the populations increased on potatoes and sunflowers. [ABSTRACT FROM AUTHOR]