香料烟灰霉病和菌核病病原鉴定及室内药剂筛选

Causal Pathogen Identification of Gray Mold Rot and Sclerotinia Rot on Oriental Tobacco and Indoor Screening of Fungicides

为明确保山地区香料烟新发生的“黑秆病”和“白秆病”病原及候选化学防治药剂,本研究依据柯赫氏法则,分离、验证病原物致病性,以形态学和分子生物学技术结合鉴定病原物种类,同时运用平板法检测11种杀菌剂对病原菌菌丝生长的抑制效果。结果表明,“黑秆病”,病原为灰葡萄孢菌(Botrytis cinerea Pers.:Fr.),命名为香料烟灰霉病,病原菌对50%多菌灵、70%甲基硫菌灵高度敏感,对55%菌核净-锰锌中度敏感,EC50分别为0.03、0.80和6.50 mg/L;“白秆病”,病原为核盘菌[Sclerotinia sclerotiorum(Lib.)de Bary],命名为香料烟菌核病,该病原菌对50%多菌灵、45%王铜-菌核净、70%甲基硫菌灵和55%菌核净-锰锌高度敏感,EC50分别为0.60、1.05、1.13和1.90 mg/L。本研究明确了保山地区香料烟2种未知病害的病原物,并获得了敏感性较高的杀菌剂。

To control two unknown diseases that seriously affect the yield and quality of oriental tobacco in the Baoshan area of Yunnan province,pathogens were identified based on their morphological,cultural properties and pathogenicity,and confirmed by molecular characterization using ITS regions.The effects of 11 fungicides on pathogen hyphal growth were also tested using the mycelial growth rate method.The results showed that the causal agents of gray mold rot and Sclerotinia rot are Botrytis cinerea Pers.:Fr.and Sclerotinia sclerotiorum(Lib.)de Bary,respectively.Results of the fungicides test showed that the pathogen of gray mold rot is highly sensitive to 50%carbendazim and 70%thiophanate-methyl with the median effective concentration(EC50)to B.cinerea hyphal growth at 0.03 and 0.80 mg/L,respectively.The pathogen is moderately sensitive to 55%dimetachlone-mancozeb with an EC50 value of 6.50 mg/L.Among the tested fungicides,50%carbendazim,45%copper oxychloride-dimetachlone,70%thiophanate-methyl and 55%dimetachlone-mancozeb showed strong toxicities to S.sclerotiorum hyphal growth with the EC50 values of 0.60,1.05,1.13 and 1.90 mg/L,respectively.To our knowledge,this is the first report of B.cinerea and S.sclerotiorum causing gray mold rot and Sclerotinia rot on oriental tobacco in China,and pesticides screened in this study will aid local farmers and tobacco technicians in disease control.