一种大蒜叶枯病新病原菌鉴定与药剂敏感性测定

Identification and fungicide sensitivities of a new pathogen causing leaf blight of garlic

【目的】探究引起大蒜叶枯的一种新病原菌及其对杀菌剂的敏感性,为生产上大蒜叶枯病防治提供科学依据。【方法】采用常规组织分离方法获得病原菌菌株,通过病原菌形态特征、致病性测定及分子生物学技术对菌株进行鉴定,并采用菌丝生长速率法研究菌丝生物学特性,测定病菌对杀菌剂的敏感性。【结果】依据菌株的形态学和分子生物学特征,确定引起大蒜叶枯的一种新病原菌为球毛壳菌(Chaetomium globosum)。该病菌菌丝生长最佳培养基为玉米培养基,最佳碳源为D⁃果糖,最佳氮源为酵母浸粉,适宜pH为7.0。菌丝生长对质量浓度分别为2400 mg/L的72%甲霜·锰锌可湿性粉剂、700 mg/L的70%甲基硫菌灵可湿性粉剂、330 mg/L的500 g/L戊唑多菌灵悬浮剂、830 mg/L的50%腐霉利可湿性粉剂、300 mg/L的45%咪鲜胺微乳剂和600 mg/L的60%唑醚·代森联水分散粒剂均极为敏感;唑醚·代森联、苯甲·嘧菌酯、代森锌、甲霜·锰锌和丙森锌对该病菌菌丝EC50分别为0.0053、0.1792、0.5162、3.0539和4.2175 mg/L。【结论】球毛壳菌是引起大蒜叶枯的新病原真菌,可侵染大蒜叶片,造成叶片枯黄,病害定名为大蒜球毛壳型叶枯病;测定出该病原菌对6种供试杀菌剂高度敏感,唑醚·代森联、苯甲·嘧菌酯和代森锌对该病原菌毒力高,可作为生产上防治大蒜球毛壳型叶枯病害的药剂。

【Objective】The present paper aimed to explore the new pathogens causing garlic leaf blight and its sensitivity to fungicides,so as to provide scientific basis for the control of garlic leaf blight in production.【Method】The pathogen strains were obtained by conventional tis⁃sue isolation method.The strains were identified by pathogen morphological characteristics,pathogenicity determination and molecular bio⁃logical technology.The biological characteristics of hyphae and susceptibility of the strain to fungicides were studied by mycelial growth rate method.【Result】According to the morphological and molecular biological characteristics of the strain,it was determined that a new pathogen causing garlic leaf blight was Chaetomium globosum.The best medium for the pathogen was corn medium,the best carbon source was D⁃fruc⁃tose,the best nitrogen source was yeast extract powder,the suitable pH was 7.0,and 72%metalaxyl⁃mancozeb WP 2400 mg/L,70%thio⁃phanate⁃methyl WP 700 mg/L,500 g/L tebuconazole⁃carbendazim SC 330 mg/L,50%procymidone WP 830 mg/L,45%prochloraz ME 300 mg/L and 60%pyraclostrobine⁃metiram WG 600 mg/L exhibited good inhibition effects on the pathogen.The EC50 of pyraclostrobine⁃metiram,difenoconazole⁃azoxystrobin,tiezene,metalaxyl⁃mancozeb and propineb were 0.0053,0.1792,0.5162,3.0539 and 4.2175 mg/L,respectively.【Conclusion】C.globosum is a new pathogenic fungus causing garlic leaf blight,which can infect garlic leaves and cause leaf withering and yellowing,the disease was named as C.globusum leaf blight of garlic;Six kinds of fungicides with good inhibition to the mycelium are selected,pyraclostrobine⁃metiram,difenoconazole⁃azoxystrobin,tiezene are highly toxic to the pathogenic fungi,so can be used as effective agents to control the new leaf blight in production.