Controlling Common Bacterial Blight in Organic Beans

Common bacterial blight of field beans, caused by Xanthomonas campestris pv. phaseoli, leads to 25–60% yield loss globally. Symptoms include pitted brown spots on cotyledons, wet translucent lesions on leaves with exudates in humidity, and water-soaked spots on pods that enlarge and crust over. Stem splitting releases yellow exudates. The pathogen survives in seed over 15 years and spreads via contaminated seed, equipment, insects, and weather. Early pod infection causes shrivelling; seedlings show initial spots on cotyledons. Defoliation and reduced seed quality occur in mature plants. Image shows symptomatic bean plants.