The results of inoculating corn seedeing with Helminthosporium turcicum and treating corn root cap cells with cultural filtrates of H. turcicum indicated that H.turcicum could produce pathotoxin either in vivo or in vitro.

• 用大斑菌接种玉米幼苗和用大斑菌的培养滤液处理玉米根冠细胞的试验证明,大斑菌无论在体内或体外均能产生致病毒素。