Incidence and Distribution of Potato Viruse Diseases in West Arsi and West Shewa Major Potato Growing Areas, Ethiopia

Abstract

Field surveys were carried out in West Arsi and West Shewa administrative zones to determine incidence of potato viruse diseases. Limited information is available on major potato viral diseases in these areas. Virus-like symptomatic leaf samples were collected from 13 districts in 71 fields for the serological detection of the common potato viruses. Field disease incidence was visually assessed based on viral disease symptoms and the identities of the viruses were tested by double antibody sandwich (DAS)-ELISA. During the field surveys, virus-like symptoms were more common in West Arsi than in West Shewa. The serological test results showed that potato virus X (PVX) (50 %) was the most predominant followed by potato virus S (PVS) (38 %), potato leaf roll virus (PLRV) (11 %) and potato virus Y (PVY) (2 %). Mixed infections of PVX and PVS were noticed in all surveyed areas, while PVY coinfection was the least detected combination with any of the tested viruses.The high incidence of PVX and PVS is most likely attributed to their mode of mechanical transmissions. PLRV transmission by aphid in a persistent manner might have favored its higher incidence as compared to PVY that is transmitted by aphids in a non-persistent manner. Of the total assayed samples, 93 %, 86 %, 73 %, 74 %, 71 %, 70 %, 69 %, 59 %, 57 %, 50 %, 48 %, 20 % and 19 % at Arsi-Negele, Shashamne, Kofele, Ambo, Jibat, Holeta, Adea-Berga, Guder, Tikur-Inchini, Wonchi, Jeldu, Dendi and Elifeta were tested positive for at least one of the assayed viruses, respectively. The high occurrence of the viruses could be attributed to different factors including recycling of the infected potato tubers and cropping system, overlapping of potato growing seasons, presence of biological vector inside potato field and infected volunteer potato from previous seasons. Overall, more than 50 % of the assayed samples were tested positive for at least one virus in the majority of the surveyed fields.
Current crop yield losses due to the pathogen need to be quantified with independent studies so as to determine the magnitude of the problem in these areas.