The bacteria in these lesions are commonly spread by wind blown rain and infects other bean plants via stomata, hydathodes and wounds. Other means of bacterial dispersal include wind blown dirt particles, contaminated irrigation water, physical contact between plants, humans and animals and insects including white flies and certain other leaf feeding insects. Once the disease is established, numerous lesions are produced on aerial plant parts as serve as an inoculum source for secondary spread of the disease. The bacterium is also capable of growing epiphytotically on weedy hosts. Symptoms Common blight symptoms are initially visible as small water-soaked spots on leaf margins or between the veins.
Spots eventually dry and turn brown.
They are surrounded by narrow band of lemon yellow tissue. Spots enlarge with age and blight large areas of leaf tissue. Heavily infected leaves may become tattered when wind whipped. In severe cases they die and remain attached to the plant. Pod infections also begin as water-soaked spots.