Pathogen Identification And Fungicides Screening Of New Diseases Of Moyeam

With the expansion of the planting area of moyeam in Zhangjiajie,China,the occurrence of moyeam diseases is becoming more and more serious,resulting in reduced production and economic losses.From 2019 to 2021,the laboratory investigated the diseases of moyeam in Yongding District,Zhangjiajie city,and found several new diseases.In this study,pathogen isolation and purification,pathogenicity tested,morphology and molecular biology identification,and laboratory toxicity test were carried out for the pathogen of leaf spot of moyeam.In addition,laboratory toxicity test and field efficacy test was carried out for the pathogen of moyeam canker isolated and identified by laboratory.The results were as follows:1.Pathogen identification of leaf spot of moyeamA new disease was found on the leaf spot of moyeam in Yongding District,Zhangjiajie city.Leaf spot samples were collected,isolated and purified to get strain YB.By morphological observation,pathogenicity tested and phylogenetic analysis of ITS andβ-tubulin genes,leaf spot of moyeam was determined to be caused by Pestalotiopsis microspora.2.Inhibition test to moyeam pathogens of fungicidesIn this study,nine fungicides（10%Difenoconazole water dispersible granules、50%Thiram wettable powder、75%Chlorothalonil wettable powder、70%Thiophanate-methyl wettable powder、0.3%Tetramycin aqueous solution、1%Phenazino-1-carboxylic acid suspension concentrate、80%Mancozeb wettable powder、0.5%Berberine aqueous solution and 2%Matrine aqueous solution）were tested on target moyeam leaf spot pathogen.The results showed that 10%Difenoconazole water dispersible granules、70%Thiop hana te-methyl wettable powder、2%Matrine aqueous solution and 0.3%Tetramycin aqueous solutionhad the well efficacy to moyeam leaf spot disease with EC₅₀0.060mg/L、0.489mg/L、0.684mg/L and 0.757mg/L.Five fungicides（0.3%Tetramycin aqueous solution、1%Phenazino-1-carboxylic acid suspension concentrate、80%Mancozeb wettable powder、0.5%Berberine aqueous solution and 2%Matrine aqueous solution）were tested on target moyeam canker pathogen,0.3%tetramycin aqueous solution+agricultural olive oil synergist、0.3%tetramycin aqueous solutionand and 80%Mancozeb wettable powderhad good efficacy on moyeam canker with EC₅₀0.074mg/L、0.094mg/L and 0.240mg/L,80%Mancozeb wettable powder had good efficacy on moyeam canker,but poor efficacy on moyeam leaf spot disease.3.Field trials of fungicides on moyeam cankerFive fungicides（0.3%Tetramycin aqueous solution、1%Phenazino-1-carboxylic acid suspension concentrate、80%Mancozeb wettable powder、0.5%Berberine aqueous solution and 2%Matrine aqueous solution）were tested on field experiments on moyeam canker.The results showed that 0.3%tetramycin aqueous solution+agricultural olive oil synergist had the best control effect on moyeam canker.The average control effect was 62.41%.