EPIDEMIOLOGY AND MANAGEMENT OF COMMON BACTERIAL BLIGHT ON COMMON BEAN VARIETIES (Phaseolus vulgaris L.) IN GUJI ZONE, SOUTHERN ETHIOPIA

Common bacterial blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli is a major constraint to common bean production globally by significantly reducing both yield and seed quality. The objective of this study was to investigate the effectiveness and economic viability of integrated CBB management strategies using seed treatment, chemical control, and genetic resistance of common beans in Ethiopia. To this end, three bean varieties (KAT-B1, Awash-1, Awash-2) were subjected to different disease control factors: seed treatment with streptomycin, foliar application of copper hydroxide at two frequencies, and an untreated control. Results showed significant interactions (p < 0.05) between variety, seed treatment, and foliar spray frequency on disease severity (DS) and yield parameters. Awash-2, a resistant variety, exhibited the lowest DS and progression. Streptomycin seed treatment combined with two Kocide-101 sprays significantly reduced CBB severity and increased yield (36% over the control) in both susceptible and moderately resistant varieties. Economic analysis revealed that seed treatment with two foliar sprays on Awash-2 provided the highest gross field benefit (ETB93893.00) compared to the control (ETB62603.00). Therefore, treating seeds with streptomycin and applying two foliar sprays of Kocide-101 on the resistant variety Awash-2 is recommended for optimal and economically feasible control of CBB for south Ethiopia and similar agro-ecological areas. Keywords: Economic returns, Disease severity, integrated disease management, Xanthomonas axonopodis