Fusarium heterosporum associated with paspalum ergot in eastern Australia

Isolates of Fusarium graminum from heads of Paspalum dilatatum infected with Claviceps paspali were compared with isolates from soil which had been identified as F. graminum or F. heterosporum on the basis of conidial characters in an earlier study. Differences between isolates were found only in the degree of pigmentation and in the length of macroconidia. Colony morphology, growth rates, and responses of growth to temperature and osmotic potential were Similar in all isolates. It was concluded that all isolates belonged to a single species, F. heterosporum. Crossing experiments indicated that the fungus may be homothallic, although ascospores were rare under the conditions used. None of the isolates tested was toxigenic.