Foto-Resumo- Sheila

Prelecionista: Sheila M. P. Andrade. Data: 05/05/2021, às 08:30 horas pelo ZOOM*. Orientador: Emerson M. Del Ponte.

Fusarium Head Blight (FHB) is a fungal disease of small grains caused mainly by Fusarium graminearum. In Brazil, disease management depends heavily on fungicide sprays that include a mixture of triazoles (DMIs) and strobilurins (QoI). Comprehensive information on the sensitivity/resistance of the fungal pathogen to fungicides is available only for DMIs, while for QoIs data are scarce and controversial. A total of 225 strains were studied in this work and the sensitivity profiles were determined in vitro for azoxystrobin and pyraclostrobin. Overall, subcollections from Rio Grande do Sul and Paraná states were seven times more sensitive to pyraclostrobin than azoxystrobin, and no correlation was found between these EC50 values for these fungicides. Significant increase over the years was observed for the frequency of less sensitive strains, especially to azoxystrobin. Sequence alignments showed no point mutation in any hot spot (F129L, G137R, G143A) even in the isolates with high EC50 (> 100 ppm). Although the sensitivity profile for F. graminearum populations was determined, mechanisms associated with QoI fungicides remain unclear.

 

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