四川省中江县丹参叶斑病病原鉴定与抑菌药剂筛选

Pathogen identification and fungicides screening of leaf spot disease on Salvia miltiorrhiza in Zhongjiang county,Sichuan province

【目的】明确危害四川省中江县丹参生长的叶斑病病原菌种类,研究常用杀菌剂对该病原菌菌丝生长的抑制作用,为丹参叶斑病的科学防控提供参考依据。【方法】采用组织分离和单孢分离对引起丹参叶斑病的病原菌进行分离和纯化,根据柯赫氏法则将分离纯化得到的叶斑病病原菌采用损伤接种菌饼的方法接种到丹参健康叶片上,测定叶斑病病原菌的致病性,并观察形态特征;利用真菌rDNA-ITS序列通用引物ITS1/ITS4,以及ACT(肌动蛋白)、GAPDH(甘油醛-3-磷酸脱氢酶)基因对叶斑病菌株进行分子鉴定;采用菌丝生长速率法测定5种常用杀菌剂对叶斑病病原菌菌丝生长的抑制效果,建立毒力回归方程,筛选出有效的抑菌药剂。【结果】结合叶斑病病原菌的致病性测定、菌落形态特征观察和rDNA-ITS序列分析结果,明确引起中江县丹参叶斑病的病原菌为果生炭疽菌(Colletotrichum fructicola)。80%代森锰锌可湿性粉剂、80%乙蒜素乳油、250 g/L嘧菌酯悬浮剂、50%醚菌酯水分散粒剂、500 g/L氟啶胺悬浮剂等5种药剂对叶斑病病原菌的菌丝生长均具有一定的抑制效果,其中80%乙蒜素乳油EC50值相对最低,为19.18μg/mL,表现出较强的抑菌效果。【结论】明确引起中江县丹参叶斑病的病原菌为果生炭疽菌(C.fructicola),80%乙蒜素乳油对叶斑病病原菌的菌丝生长具有较强的抑制效果,可用于该病害的防控。本研究为丹参叶斑病的防控提供了理论依据。

【Objective】The purpose of the study is to provide a scientific basis to control leaf spot disease on Salvia miltiorrhiza which hap⁃pends in Zhongjiang county,Sichuan province,by identifying pathogenic fungus and screening of fungicides.【Method】The pathogen causing leaf spot disease on S.miltiorrhiza was isolated and purified by tissue separation and single spore culture,respectively.The pathogenicity of the isolate was determined according to Koch's rule and morphological characteristics were observed.The rDNA⁃ITS sequence primer ITS1/ITS4,ACT(actin)and GDPH(glyceraldehyde⁃3⁃phosphate dehydrogenase)genes were used for molecule biology identification.Five fun⁃gicides were used to determine the inhibition effect on that pathogen,and the toxicity regression equation of them was also established.【Re⁃sult】Combined with pathogenicity,colonymorphological characteristics and rDNA⁃ITS sequence analysis results,the pathogen was identified as Colletotrichum fructicola.The five fungicides including 80%Mancozeb WP,80%Ethylicin EC,250 g/L Azoxystrobin SC,50%Kresoxim⁃methyl WG,and 500 g/L Fluazinam SC,had a certain inhibitory effect on mycelium growth,and the EC50 value of 80%Ethylicin EC was 19.18μg/mL,which showed a strong inhibitory effect.【Conclusion】The pathogen causing leaf spot disease on S.miltiorrhiza to happen in Zhongjiang county was C.fructicola.80%Ethylicin EC had the strongest antibacterial activity and could be used for the prevention and control of the leaf spot disease.The study provides a theoretical basis for the treatment of leaf spot on S.miltiorrhiza.