[Aims]This study aims to evaluate the application prospect of pyraclostrobin·boscalid 38％WG for the control of tobacco target spot.[Methods]The mycelial growth rate method was used to determine the inhibitory activities of pyraclostrobin,boscalid and pyraclostrobin boscalid 38％WG against tobacco target spot pathogens;and the changing rules of the structure and diversity of the phyllosphere fungal and bacterial communities in tobacco were analyzed after the application of pyraclostrobin·boscalid 38％WG by the Illumina Hiseq high-throughput sequencing technology.[Results]Pyraclostrobin,boscalid and pyraclostrobin·boscalid 38％WG all had strong activities against the mycelium growth of tobacco target spot pathogen.The EC50 values were 0.26,1.58 and 0.24 mg/L.Before application of fungicides,the predominant phyllotropic fungi of tobacco leaves at the damage stage of tobacco target spot were Thanatephorus,Botrytis and Cercospora,and the dominant bacterial genera were Pseudomonas,Methylbacterium,Pantoea and Sphingomonas.The structure and diversity of fungal and bacterial communities in infected and healthy tobacco leaves were altered upon application.Among them,the relative abundance of Thanatephorus was significantly reduced in susceptible areas after application;the relative abundance of 3 species of bacteria including Masseillae.was significantly reduced on day 1 and 3 after application,and that of 6 species of bacteria including Pantoea.reduced on day 9 and 18 after application;the relative abundance of 7 fungal genera including Fusarium.increased and then decreased,and that of 4 species of bacteria including Methylobacterium.increased after application.[Conclusions]The differences in the phyllosphere microecological changes between diseased and healthy tobacco tissues at different periods after the application of pyraclostrobin·boscalid 38％WG were revealed,which provides a reference basis for the application of this agent for the prevention and control of tobacco target spot disease.
维普
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