The bacterium is seed-borne. Rain or irrigation water is necessary for movement of the organism. After infection takes place, four to six days is required before lesions are visible. Optimum temperature for development is 82 degrees F. Control of this pathogen is through a combination of practices such as drainage, row spacing, seeding rates, weed control, and restricting irrigation only to that needed for maximum plant growth. All three fungi are known to attack peas.
Affected leaves have spots which are large, pale brown to dark brown in color.
Lesions are papery in appearance and have gray to tan centers marked by small black pycnidia. Infection by some species cause purple lesions. On pods, deep lesions are formed which may have purple margins. The center is tan with black pycnidia. Planting infected seed results in poor stands.