Intensity of Sweetpotato feathery mottle virus and Sweetpotato chlorotic stunt virus in Farmers and Commercial vine Propagators Fields in Selected Areas of Southern Ethiopia

Abstract

In Ethiopia, the production of sweet potato suffers from virus infections over the last two decades. To this effect, field surveys were conducted to identify and document the current incidences and severities of sweet potato viruses in farmers and commercial vine propagator fields in selected areas of Southern Ethiopia. In total, 710 leaf samples were collected from randomly selected 30 small-scale farmers’ sweet potato fields, four commercial sweet potato vine propagators and one-government research institution during 2017. The selected plants were visually examined and disease severity was recorded based on 1-5 scales. Sweet potato feathery mottle virus (SPFMV) and Sweet potato chlorotic stunt virus (SPCSV), the two most common viruses were tested using DAS-ELISA and TAS-ELISA in the Plant Tissue Culture Laboratory at College of Agriculture, Hawassa University. This study revealed that sweet potato crops in farmers and vine propagator fields were infected by both viruses. The highest average incidences of SPCSV (59.1%) and SPFMV (37%) were recorded from farmers’ fields in Boloso Sore district. The average incidences of SPFMV were 28% and 39.3% in the farmers’ fields and commercial vine propagators fields, respectively, compared to 47% and 36.6% for SPCSV in the same fields. Overall, incidences of 38.2% and 37.6% were recorded for SPFMV and SPCSV, respectively, from all samples collected from studied areas. The mean highest virus severity of 3.03 and 2.97% was recorded in the commercial vine propagator and farmers’ fields, respectively. This study revealed an increasing incidence and severity of the two viruses in the surveyed areas indicating the importance of planning for possible virus management and restrictions that limit further propagation of the planting materials from these areas to other locations where there were no reports of these viruses.