Economic loss is associated with damage to seed quality. Diaporthe phaseolorum var. The relative frequency of the two pathogens varies according to location, etc. The pathogens and spore forming structures are abundant on plant debris and my be seed transmitted. The pathogens cause a latent infection throughout plants and may be detected by culturing on media containings herbicides.
Symptoms become evident as plants approach senescence.
Symptoms and signs include the presence of perithecia and pycnidia in linear arrays on stems . Dense formation of fruiting bodies also occurs on pods. Pod infection is necessary for infection of seeds and subsequent damage. Pods are susceptible at the R7 stage. Temperatures above 20 C favor infection.