甜菜褐斑病菌对苯并咪唑类杀菌剂抗药性的研究

1980～1981年期间,自各地甜菜褐斑病病叶样本上分离出563个单孢菌株,并测定了各菌系对甲基托布津的敏感性。结果表明,山东高密、江苏东辛农场等地单独使用苯并咪唑杀菌剂3～4年以后,病菌产生了严重的抗药性,黑龙江巴彦、呼兰、山东薛城等地因没有或极少用药防治,病菌仍然表现敏感。山东菏泽、滕县等地已有一定数量的抗性菌株,但分布尚不普遍。试验证实,抗性菌株对甲基托布津、多菌灵和苯来特等三种苯并咪唑杀菌剂具有交互抗性,百菌清、醋苯锡和毒菌锡对抗性及敏感病菌均有良好效果。目前可选择百菌清作为苯并咪唑类的主要替换药剂。初步观察,停止用药后三年以内抗性菌株的数量及抗性程度仍然保持稳定。此外,甜菜频繁调种加速了抗性病菌的扩散。建议未发现抗性的地区应尽量避免从抗性严重的地区调种。

STUDIES ON RESISTANCE OF CERCOSPORA BETICOLA TO BENZIMIDAZOLEFUNGICIDES

In 1980 and 1981,563 single-spore strains of Cercospora beticola from diseased sugarbeets of different areas of China were studied.Isolates from Gaomi,Shandong and Dongxin Farm,Jiangsu,where benzimidazole fungicides had been used exclusively for 3 to 4 years were highly resistant to thiophanate methyl.The level of resistance and the propor-tion of resistant strains remained stable in 3 years after cessation of benzimidazoles usage.Isolates from Bayan,Hulan,Heilungjing and Xuecheng,Shandong,where benzimidazole:had never been used were stillsensitive.The resistant strains were cross-resistant to thiopha nate me-thyl,carbendazim and benomyl.Daconil,triphenyltin acetate and triph-eryltin hydroxide were effective to resistant and sensitive strains.Daconilwas recommended as a main substitute fungicide.