Identification and Indoor Fungicide Screening of Pathogen Causing Leaf Spot on Rehmannia glutinosa
In order to identify the pathogen species and its biological characteristics of Rehmannia glutinosa leaf spot in Jizhou area of Tianjin City,and to screen effective pesticides for controlling the pathogen of R.glutinosa leaf spot,the methods of diseased leaves collection,strain isolation,microscopic observation,in vitro inoculation,ITS,EF1-α,Tub multiple genes sequence alignment and evolutionary tree analysis were used to islolate,purify and identify the pathogen of R.glutinosa leaf spot by morphology,pathogenicity and molecular biology.The biological characteristics of the pathogen in three media and four carbon and nitrogen sources were studied.At the same time,the virulence of four fungicides was determined.The results showed that the pathogen A1 isolated from the leaf spot of R.glutinosa was Fusarium equiseti.The optimum medium,nitrogen source and carbon source were Czapek medium,glycine and sucrose,respectively.The results of laboratory efficacy test showed that 45%prochloraz aqueous emulsion had the best inhibitory effect on mycelial growth of pathogen,the concentration for 50%of maximal effect(EC50)was 63.69 mg/L,and the inhibition rate of mycelial growth was up to 83.64%.75%chlorothalonil wettable powder had the worst inhibitory effect,with EC50 of 355.06 mg/L,and the maximum inhibitory rate of mycelial growth was 64.63%.In conclusion,F.equiseti was the pathogen of R.glutinosa leaf spot in Jizhou district of Tianjin,and 45%prochloraz aqueous emulsion has the best controlling effect on the pathogen of R.glutinosa leaf spot.
Rehmannia glutinosaLeaf spotFusarium equisetiBiological characteristicsScreening of fungicides
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