Current status of bacterial wilt (Ralstonia solanacearum) disease in major seed potato (Solanum tuberosum L.) growing areas of Ethiopia

On-site assessment and detection of plant diseases is a prerequisite to inspect the health status of seed potatoes and to make cost-effective disease management decisions. The present study was conducted in 60 major seed potato producing cooperatives of Ethiopia to assess the extent of potato bacterial wilt disease and to generate information on current status of R. solanacearum. The field assessment and inspection survey was conducted during 2015/16 for 3 seasons in 140 potato fields covering 123.30 hectares of seed potato. Symptomatic plants were confirmed for R. solanacearum by Agri Strip kit, potassium hydroxide (KOH) test and vascular flow (VF) techniques. The results of the study indicated that out of 140 seed potato fields assessed, 26 (equivalent to 18.57%) or some 33.3% of seed cooperatives were infested by bacterial wilt. The highest disease incidence (82.5%) was recorded in Jeldu district followed by Wonchi district (60%) where most of seed potato is being distributed to the country. Based on the results of three disease confirmation tools (Agri Strip, KOH and VF) implemented, 34.75 (28.18%) hectares of the fields showed positive results. Disease prevalence ranged from 0 to 100%. In some districts like Cheha, Doyo-gena and Shashamane, the disease prevalence was 100%, whereas 50% disease prevalence was recorded in Arsi-Negelle and Kofole districts. This study describes the current infestation level of bacterial wilt in major seed producing cooperatives of Ethiopia and potato production is highly threatened by Ralstonia solanacearum in most of the areas addressed by this survey