Usually, the disease is confined to lower leaves unless conditions are conducive to epidemic development . Pods and seeds may also become infected. The pathogen overwinters in residue and seed. It is a seedborne disease. Cotyledons are the site of primary infection.
Secondary infections occur on leaves, pods, and stems.
Infection results in the production of phytotoxins and bacterial slime and eventually lesions. Control Measures use less susceptible cultivars. This disease is normally a minor problem, and yield loss data are difficult to confirm, but concerns about seed-borne transmission have resulted in import restrictions being imposed by European countries. First reported in 1941 in Illinois, this disease is now widespread in the United States. The causal agent is Philophora gregata .