Blight
Blight is a rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral organs. Accordingly, many diseases that primarily exhibit this symptom are called blights. Several notable examples are:
Halo blight
The seed is a source of inoculum and pathogen survives in seeds from the previous year. The pathogen of halo blight can overwinter in previously infected bean debris, contaminated seeds, weed hosts or volunteer beans. Halo blight can be dispersed by contact between wet leaves, rainfall, irrigation or people and animals moving through infested fields. The Pathogen can enter in either plant injuries or the natural openings in plants such as stomata and hydathodes during periods of high humidity or when the foliage is wet. Then the pathogen survives from defense mechanisms in intracellular spaces and obtain nutrients from the host. After 6–10 days of infection, bacteria oozes from lesions which causes secondary infections.