穿龙薯蓣立枯病的病原鉴定及其对杀菌剂的敏感性

Pathogen Identification of Seedling Blight of Dioscorea nipponica and Its Susceptibility to Fungicides

利用组织分离法对穿龙薯蓣立枯病罹病植株茎段进行病原菌的分离。获得了8个具有致病性的菌株,并对其形态学和培养学性状进行了观察。结果表明:茄立枯丝核菌(Rhizoctonia solani Kühn)为该病害的病原菌。采用常规玻片对峙培养法进行病菌菌丝融合群测定及菌株rDNA-ITS区序列分析,结果均表明,该病原菌属茄立枯丝核菌AG-1-IB亚群。病原菌的室内药剂敏感性测定结果表明:病菌对达克宁、适乐时和异菌脲敏感性最高(EC50<0.5 mg/L);对农利灵、腐霉利和瑞和戊菌唑的敏感性次之(1mg/L<EC50<2 mg/L);对阿米西达、杀毒矾和代森锌也具有一定的敏感性(3 mg/L<EC50<4 mg/L);对春雷霉素和福美双的敏感性相对较差(EC50>5 mg/L)。

The seedling blight of Dioscorea nipponica was first reported in China. Eight isolates with pathogenicity were obtained from stems of diseased plants by the method of tissue isolation. Their characteristics of morphology and cultivation were investigated. Results demonstrated that Rhizoctonia solani Kuehn was the pathogen of seedling blight of D. nipponica. Anastomosis groups were determined to be AGI-IB subgroup by pairing isolates with tester strains and sequence analysis of rDNA-ITS re- gion. The test of susceptibility to fungicides showed that the pathogen was most sensitive to ehlorothalonil, fludioxonil and ipredione （ EC50 〈0.5 mg/L） , followed by vinclozolin, procymidone, and peneonazole （ 1 mg/L〈EC50 〈2 mg/L）, amistar, sandofan and zineb （3 mg/L〈EC50〈4 mg/L）, while it was most resistant to kasugamycin and Thiram （EC50〉5 rag/L）.