This article by Moyer and Salazar, outlines the viruses and virus like diseases affecting sweetpotato crop. Due to renewed interest of the  international agricultural community in sweetpotato, there is need for development of improved varieties. These varieties are needed for germplasm maintenance, commercial production and research purposes. From field observations and assays, virus symptoms and presence of one or more viruses in all sweetpotato even those grown from non-infected material have been witnessed. This means that necessary precautions must be taken to prevent the inadvertent distribution of viruses through germplasm.