A comparative study of Diaporthe/Phomopsis fungi on soybean from two different regions of the world.

A comparative study was conducted with soybean material presenting symptoms of the Diaporthe/Phomopsis complex that was collected in two distant geographical regions of the world: Beltsville, MA, USA, and Vojvodina, Yugoslavia. Contrasting with earlier findings, great variability in the disease symptoms was observed, and one or more Phomopsis species could be isolated from lesions presenting similar characteristics. Among the thirty-three isolates obtained from the lesions the following species were identified: D. phaseolorum var. caulivora, P. phaseoli (teleomorph D. phaseolorum var. sojae, rare), P. longicolla (found for the first time on the soybean fields of Yugoslavia), Phomopsis sp., and one culture showing intermediate characters of D. phaseolorum var. caulivora and D. phaseolorum var. sojae. Much diversity was also found in the cultural characters of the the isolates from both localities, presumably indicating evolutionary and adaptation processes.