FUSARIUM HETEROSPORUM ASSOCIATED WITH PASPALUM ERGOT IN EASTERN AUSTRALIA

Isolates of Fusarium graminum from heads of Paspalum dilatatum infecte d with Claviceps paspali were compared with isolates from soil which h ad been identified as F. graminum or F. heterosporum on the basis of c onidial characters in an earlier study. Differences between isolates w ere found only in the degree of pigmentation and in the length of macr oconidia. 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. heterosp orum. Crossing experiments indicated that the fungus may be homothalli c, although ascospores were rare under the conditions used. None of th e isolates tested was toxigenic.