Viruses and Virus Disease Complexes of Sweetpotato

Sweetpotato is an important crop for food security in many developing countries. Surveys have consistently listed virus diseases, especially sweetpotato virus disease (SPVD), as the most important diseases of this crop, yet they remain the most difficult diseases to manage. Much has been learned about sweetpotato viruses from independent research programs in different countries in recent years. Although there are indications that some viruses are yet to be isolated and characterized, there are at least 15 well characterized viruses now known from sweetpotato. It has become evident that sweetpotatoes are often infected by complexes of viruses and that interactions among these viruses influence the symptoms and yield losses. The crinivirus, Sweet potato chlorotic stunt virus (SPCSV), can greatly enhance the activity not only of the other key component of Sweet potato feathery mottle virus (SPFMV, a potyvirus), but also a number of other unrelated viruses. SPCSV will be the primary focus of future research to understand and control sweetpotato virus disease complexes. Sweetpotato begomoviruses are more widely distributed than previously recognized and may also require attention. International scientific exchange and collaboration could help determine why SPVD occurs in some countries but not others and provide insight to controlling this disease in the future. _____________________________________________________________________________________________________________