Australia

Common bacterial blight

Xanthomonas axonopodis pv. phaseoli (Xanthomonas campestris pv. phaseoli)

Common bacterial blight affects the foliage and pods of the common bean and soybean. Symptoms initially appear as small, water-soaked spots (lesions) on the leaves. The lesions gradually enlarge and coalesce into irregular shapes, frequently one inch or more in diameter, and they exhibit a scalded appearance. The lesions may become dry and brown and surrounded by a narrow, lemon-yellow-colored margin. The lesions frequently occur along leaf margins. Infected pods may exhibit circular, slightly sunken, water-soaked areas. In humid conditions, infected areas on the pods may produce yellow masses of bacterial ooze. The infected areas on the pods usually dry to become reddish-brown lesions, and pod infections frequently result in discolored and shriveled seeds.