Bacterial Blight or Xanthomonas phaseoli causes characteristic leaf symptoms of common blight, consisting of irregular areas of brown dry tissues surrounded by a narrow lemon yellow border. These lesions frequently occur at the leaf margins. Pods have sunken circular spots, at first water-soaked, but later dry, with a reddish brown narrow border. The bacteria invade the seeds and remain dormant until germination begins. Even a trace of infected seed when planted can initiate severe infection of entire fields. The bacteria exude in the leaf and pod spots and are spread mainly by splashing and blowing rain. Warm, humid conditions favor development of the disease.