Distribution and association of factors influencing bean common bacterial blight (Xanthomonas axonopodis pv. phaseoli) epidemics in Southern Ethiopia

Abstract

Field surveys were conducted to determine the spatiotemporal distribution and the association of disease intensity with cropping systems and other environmental factors in Southern Ethiopia during 2016 and 2017. In both years, a total of 190 bean fields were surveyed in five districts, and common bacterial blight (CBB) was 100% prevalent. But disease incidence and severity varied among districts and between cropping years. Bean planting in Arbaminch suffered from 31% to 38%, 6–13%, 12–17% and 8–12% higher CBB severity than bean cultivation in Burjdi, Mihirab Abaya, Demba Gofa and Konso districts, respectively. The associations of disease parameters with independent factors were assessed using the logistic regression analyses. District, cropping year, altitude, land preparation, cropping system, fertiliser application, planting date, growth stage and weed infestation were associated with both disease incidence and severity with variable levels of significance. Common bean genotype was also significantly (P < .005) associated with disease severity in a multiple variable model. Concerning incidence, variable associations were demonstrated by the model. These results indicate that CBB is severe and highly prevalent in Southern Ethiopia. Therefore, efforts should be geared towards crop residue management, optimal tillage and fertiliser application, weeding, clean seed source and early planting approach to manage the disease.