Identification,biological characteristics and screening of fungi-cides for Phyllanthus emblica L.spot disease pathogen
[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 ba-sis 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 pin-prick 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 viru-lence 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 characteris-tics 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 ef-fect on mycelial growth of strain PE3,with median inhibitory concentration(EC50)of 0.019 mg/L.It was followed by 8%flusilazole microemulsion,10%difenoconazole microemulsion and 25%pyraclostrobin suspension with EC50 of 0.023,0.124 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 di-sease 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.
国家科技期刊平台
NSTL
万方数据
维普
