Sweet potato virus disease (SPVD) occurs in sweet potato at all localities on the perimeter of Lake Victoria areas surveyed in Uganda and Tanzania, and was particularly common in Kagera District in Tanzania and in Rukungiri District in Uganda. All fields were planted with landraces and the most important control practices, as perceived by farmers, were the planting of cuttings derived from only symptomless parents and destroying diseased plants. Although SPVD-resistant landraces were available, they were perceived by most farmers to have poor and late yields. Most farmers considered that their greatest need was new, more acceptable, SPVD-resistant genotypes. Few farmers had seen either sweet potato seeds (15%) or sweet potato seedlings (11%) and, of those that had, most had ignored them. The lack of seedlings and their neglect by farmers is likely to be hindering the evolution of more acceptable, SPVD-resistant landraces, and is probably responsible for SPVD being a long-term disease problem.
Gibson, R.W.; Jeremiah, S.C.; Aritua, V.; Msabaha, R.P.; Mpembe, I.; Ndunguru, J. Sweet Potato Virus Disease in Sub-Saharan Africa: Evidence that Neglect of Seedlings in the Traditional Farming System Hinders the Development of Superior Resistant Landraces. Journal of Phytopathology (2000) 148 (7-8) 441-447. [DOI: 10.1046/j.1439-0434.2000.00529.x]