白及叶斑病病原菌的鉴定与室内杀菌剂筛选

Pathogen identification of leaf spot on Bletilla striata and fungicide screening in laboratory

为了鉴定广西南宁种植基地的白及叶斑病病原菌种类并筛选出高效杀菌剂,采集了典型的叶斑病样品,对这些样品进行了病原菌的分离纯化,并根据科赫氏法则验证了分离株的致病性.结合形态特征和多基因序列联合分析,鉴定了病原菌的种类,并利用菌丝生长速率法评估了10种杀菌剂对代表菌株的抑制效果.结果显示本研究成功分离出了引起白及叶斑病的病原菌,即链格孢Alternaria alternata.将该病原菌接种到健康的白及叶片上可以引起与田间病害相似的症状.在对不同杀菌剂的测定中,肟菌戊唑醇对该菌菌丝生长的抑制效果最为显著,其EC_(50)值为1.25μg/mL.

In order to identify the pathogenic fungi causing Bletilla striata cultivation disease in the planting base of Nanning,Guangxi,and screen for highly effective fungicides,this study collected typical samples of leaf spot disease.The pathogenic fungi were isolated and purified,and the pathogenicity of the isolated strains was verified according to Koch's postulates.The identification of the pathogenic fungi species was performed through a combined analysis of morphological characteristics and multi-gene sequencing.The inhibitory effects of 10 fungicides on representative strains were determined using the mycelial growth rate method.The results showed that the isolated pathogenic fungi causing B.striata leaf spot disease were identified as Alternaria alternata,a species of chain spot fungus.Inoculating the pathogenic fungi onto healthy B.striata leaf samples resulted in disease symptoms similar to those observed in the field.Among the tested fungicides,oxathiapiprolin exhibited the strongest inhibition activity against the mycelial growth of this fungus,with an EC_(50)value of 1.25μg/mL.The findings of this study provide scientific evidence for the identification and control of B.striata leaf spot disease.