Bacterial soft rot is a widespread disease in onion in different areas of Abyan Governorate. The losses due to this disease greater than other bacterial disease. The bacteria releases large quantities of enzymes and toxins which has direct impact on host. The diseased onion are source of infection for the healthy onion, and infected tissues are decomposed and turns in to slimy liquids . Infection starts in field during harvesting, transportation and storage. The findings of differences in morphological and biochemical tests in addition to potential of infection, showed that the bacteria Erwinia Carotovora, is the causal agent of soft rot on Bombay red and Bafateim onion cultivars.

Key Words :Soft rot disease, Bacteria, Onion, Abyan