Survey of potato bacterial wilt caused by Rats/ollia sotallacearum was conducted in south andrncentral zones of Ethiopia during 1996/97 cropping seasons and incidence, prevalence, latencyrnand characteristics of strains were detennined. Mean percentage wilt incidence of the disease wasrnfound to be relatively high in the irrigated areas of Bako (27.8%) and Ambo (18.2%) and inrnShashemene district in both Meher (19.8%) and Belg (22.3%) produced potato crops. Thernpercentage wilt incidence was low at Wondo Genet(7.2%), Jeldu (2.3%) and Inchini (1.3%).rnMean percentage wilt prevalence of the disease was also high in Bako (87.5%), Shashemenern(Belg, 75%; Meher, 70%), Ambo (70%) and Wondo Genet (62.5 %) and low in Jeldu (17.5%)rnand Inchini (7.5%). Assessment of preceding crop on bacterial wilt development showed that successive potatorn. cropping resulted in more disease development than preceded by non-host crop(s) and mean wiltrnincidences of, respectively, 35.3, and 19.1 % were recorded.rnCultural, biochemical, carbohydrate utilization, hypersensitivity reaction and pathogenicity testsrnindicated that isolates belong to biovar 2 and race 3 of R. sotallacearllm. Relative virulencernstudy showed that isolates from Bako and Ambo are more virulent while virulence of isolatesrnfrom Jeldu and Inchini are least.rnMean percentage latent tuber infection was found to be relatively high in tubers harvested fromrninfested crops at Jeldu (77.7%) and Shashemene (Meher 65.3%) followed by Wondo Genetrn(52.6%), Shashemene (Belg 53.7%), Ambo (51.2%) and Bako (45.7%), and least in tubers fromrnInchini (18.6%). In market bought tubers, high percentage infection was also recorded at Jeldurn(53.5), Wondo Genet (50.0) and Shashemene (Meher ,48.5) and least was at Inchini (6.0) On investigation of weed host plants as carriers of the pathogen, the pathogen was isolated fromrna common weed, Galillsoga parviflora. The bacterium was found pathogenic to potato andrntomato., but not to G. parviflora. Hence, the weed is a latent carrier of R. soiallacearlllll.rnGenerally, the disease is widespread and is a serious problem to potato production in the majorrngrowing areas of south and central zones of Ethiopia.