Common bacterial blight (CBB) caused by Xanthomonas axonopodis pv. phaseoli is the most important biotic production constraint to common bean in eastern Ethiopia. Climate change could have an impact on the disease epidemiology by influencing both common bean growth and the pathogen reproduction. The effects of climate change needs to be mitigated using climate change resilience strategies. Field experiments were conducted in the 2012 and 2013 cropping seasons at Haramaya and Babile research stations in eastern Ethiopia to assess the effects of integrating climate change resilience strategies on CBB of common bean. Gofta (G2816) and Mexican 142(11239) common bean varieties were used. Eight climate change resilience strategies used were compost application, row intercropping and furrow planting alone and in combination. Factorial combinations of two common bean varieties and eight climate change resilience strategies totally 16 treatment combinations were studied in randomized complete block design (RCBD) with three replications and repeated once. Disease severity data were recorded from 10 randomly tagged plants from four central rows per plot. Disease severity, area under disease progress curve (AUDPC) and disease progress rate were significantly different among climate change resilience strategies, between varieties, cropping seasons and locations. Disease severities, AUDPC and disease progress rate were consistently less on row intercropping + compost application + furrow planting and row intercropping + compost application compared to singly applied climate change resilience strategies and sole planting plots in both locations and seasons. The disease epidemic was relatively higher on Mexican 142 than Gofta and during 2012 than 2013 at Babile than Haramaya. Integrated climate resilience strategies reduced CBB epidemics and could be applied as a component in management of CBB in eastern Ethiopia and in areas with similar agro-ecological zones.

Common bacterial blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli Smith (Xap) and Xanthomonas axonopodis pv. phaseoli var. fuscan Burkholder (Xapf) is the most serious biotic constraint of common bean (Phaseolus vulgaris L.) production. Variables temperature and moisture are dominant climate factors that affect common bean growth as well as the development of CBB epidemics. Two sets of experiments were conducted in the Plant Pathology Laboratory of Haramaya University) to assess the effect of temperature and moisture on the resistance level of common bean in 2014 and 2015. In the first experiment, two common bean varieties (Gofta and Mexican 142) were inoculated with two bacterial strains (Xap and Xapf) and a control were incubated at four temperature levels (28°C, 30°C, 32°C and 34°C) in growth chambers. In the second experiment, three-soil moisture levels (100%, 75% and 50%) were employed to that of experiment one. The treatment combinations were arranged in factorial completely randomized design (CRD) in the growth chambers for both series of experiments. The disease rating was significantly (P<0.05) affected by common bean varieties and temperature levels at 17 days after inoculation (DAI). Higher disease rating was recorded on the variety Mexican 142 than on Gofta. The highest (1.75) mean disease rating was recorded at 28°C and the lowest (1.44) at 34°C. The mean disease ratings differed significantly among the moisture levels. The highest (2.01) mean disease rating was recorded from 75% moisture content, while the lowest (1.80) disease rating was obtained from 50% moisture content. The results of these series of experiments indicated that climate change effects above optimum level would not be favorable for CBB development in the arid and semi-arid agro ecologies unless new bacterial strains adapted to the drought tolerant common beans in the area.