Abstract: The natural infected wild oat plants were discovered and collected in the
wheat field of Nanjing, Jiangsuprovince. The pathogen was isolated and identified, and the cultural characteristics and infective ability were also studied. The results showed that the pathogen is Drechslera avenaceae (Curtis ex Cooke) Shoem. The colonies of this fungus are grey to black, with coarse, radiating mycelium for ming characteristic large milky white to greyish turfs in PDA medium , and producing no conidiain PDA. Ascomata and some conidia could be observed on the oat seedsmedium or on wheat straw swhich cultured on the 2% agarmedium. The pathogenesis exper iments showed that this fungus only infects wildoats, not wheat. Futher development and research of this fungus as a selection of mycoherbicide for wildoats control are suggested in this paper.