余甘子斑点病病原菌鉴定、生物学特性及防治药剂筛选

Identification, biological characteristics and screening of fungicides for Phyllanthus emblica L. spot disease pathogen

  • 摘要: 【目的】明确余甘子果实斑点病的病原菌种类,了解其生物学特性,筛选有效的防治药剂,为余甘子果实斑点病的科学诊断和田间防治提供理论依据。【方法】从广东省汕尾市陆河县余甘子产业园种植基地采集发生斑点病的余甘子果实,采用组织分离法对余甘子斑点病病果进行病原菌分离,通过形态学特征和基于多基因(ITS、TUB和EF1-α)的系统发育进化分析对病原菌进行鉴定;采用针刺接种法测定病原菌菌株的致病力;采用菌丝生长速率法测定不同培养条件对病原菌菌丝生长的影响;通过室内毒力测定评估12种常见杀菌剂对病原菌的抑菌活性。【结果】从余甘子病果中分离出1株病原真菌菌株PE3,致病性测定结果表明,该菌株为余甘子斑点病致病菌,其形态特征与间座壳菌Diaporthe phoenicicola相似,且其ITS、TUB和EF1-α基因系统发育进化树分析显示与D.phoenicicola聚在同一分支。生物学特性测定结果显示,菌株PE3菌丝生长的最适温度为25℃,最适p H为7,最适生长碳源为甘油和蔗糖,最适生长氮源为酵母提取物。室内毒力测定结果显示,450 g/L咪鲜胺乳油对菌株PE3菌丝生长的抑制作用最强,抑制中浓度(EC50)为0.019 mg/L;其次是8%氟硅唑微乳剂、10%苯醚甲环唑微乳剂和25%吡唑醚菌酯悬浮剂,EC50分别为0.023、0.124和0.194 mg/L;而2%春雷霉素水剂对菌株PE3菌丝生长的抑制效果最差,EC50为402.336 mg/L。【结论】间座壳菌D.phoenicicola是引起余甘子果实斑点病的病原菌,450 g/L咪鲜胺乳油、8%氟硅唑微乳剂、10%苯醚甲环唑微乳剂和25%吡唑醚菌酯悬浮剂能有效防治余甘子果实斑点病,可在余甘子种植中推广应用。

     

    Abstract: 【Objective】The purpose of the study was to identify the pathogen species of Phyllanthus emblica L.fruit spot disease,to understand its biological characteristics,to screen the effective fungicides,and to provide theoretical basis for the scientific diagnosis and field control of P.emblica fruit spot disease.【Method】The P.emblica fruits with spot disease were collected from the planting base of P.emblica industrial park in Luhe County of Shanwei city,Guangdong Province.Tissue separation method was used to isolate pathogens from P.emblica fruits with spot disease.The pathogens were identified by morphological characteristics and phylogenetic evolutionary analysis based on multiple genes (ITS,TUB and EF1-α).The pathogenicity of the pathogen strains was determined using the pinprick inoculation method.The effects of different culture conditions on the mycelial growth of pathogens were determined based on the mycelium growth rate method,and the inhibition activities of 12 common fungicides against the pathogen were evaluated by indoor virulence assay.【Result】A pathogenic fungus strain PE3 was isolated from the diseased fruit of P.emblica.The pathogenicity test results showed that this strain was the pathogen causing the spot disease of P.emblica.Its morphological characteristics were similar to those of Diaporthe phoenicicola.Phylogenetic tree analysis of its ITS,TUB and EF1-α genes showed that it was clustered in the same branch with D.phoenicicola.The results of biological characteristics measurements showed that the optimum temperature for mycelial growth of strain PE3 was 25℃,the optimum pH was 7,the optimum carbon sources for growth were glycerin and sucrose,and the optimum nitrogen source for growth was yeast extract.The results of indoor virulence assay showed that 450 g/L prochloraz emulsifiable concentrate had the strongest inhibition effect on mycelial growth of strain PE3,with median inhibitory concentration(EC50) of 0.019 mg/L.It was followed by8%flusilazole microemulsion,10%difenoconazole microemulsion and 25%pyraclostrobin suspension with EC50 of0.023,0.124 and 0.194 mg/L,respectively.However,2%kasugamycin aqueous solution had the worst inhibition effect on mycelial growth,with EC50 of 402.336 mg/L.【Conclusion】D.phoenicicola is the pathogen causing the fruit spot disease in P.emblica.The 450 g/L prochloraz emulsifiable concentrate,8%flusilazole microemulsion,10%difenoconazole microemulsion and 25%pyraclostrobin suspension can effectively prevent and control the fruit spot disease of P.emblica,which can be promoted and applied in P.emblica planting.

     

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