本文报道稻瘟病(Pyricularia oryzae)病原菌粗毒素的提取方法及其对水稻的致病性。试验表明E_3和F_1小种的菌落生长随培养基和培养时间不同而有明显差异。四种培养基中以山口富夫的液体培养基培养四周,菌落生长最佳,毒力最强。粗毒素滤液对水稻幼苗有致病性,叶片微针注射时,出现局部细胞群坏死,形成棕色环状病灶。幼苗根部浸泡后,叶片卷缩、凋萎、褪色明显。 This paper reports the extraction of crude toxins from the pathogen of Pyricularia oryzae and its pathogenicity to rice. The experiment showed that the colony growth of E_3 and F_1 races differed significantly with the culture medium and culture time. Four kinds of culture medium to Shafu Fufu liquid culture medium for four weeks, the best colony growth, the strongest virulence. Crude toxin filtrate has pathogenicity on rice seedlings. When the microneedles are injected, local cell group necrosis appears and a brown annular lesion is formed. After soaking the roots of the seedlings, the leaves are crimped, wilted and faded obviously.