Diaporthe phaseolorum.var. caulivorum
According to recent studies in Italy, on imported soybean seed from USA, D. phaseolorum var. caulivorum has been identified as well as var. sojae.
Some of the isolations of D. phaseolorum turn out to be the more dangerous variety, which, though not yet added to the EPPO Al List of quarantine organism, is actively under study as a candidate.
Sources
Bertoline, P. and Tanzi, M. (1987) (Pathogenic mycoflora of soybean seeds) Informatore Fitopatologico 37, (10), 39-42.