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Etiology and quantification of causal agents of wheat leaf spots in 2008 to 2011 growing seasons

The wheat (Triticum aestivum L.) crop is one of the most important options for cultivation in the winter season. Among the foliar diseases, yellow leaf spot, brown-spot and septoriosis, are cited as the most frequent leaf spot in wheat. This study aimed to identify and quantify the pathogenic fungi associated with leaf spot symptoms in wheat cultivars in Regions of Value for Cultivation and Use (RVCU). One hundred and sixty two samples collected in 2008 to 2011 season, in wheat field in the states of Paraná, Santa Catarina, Minas Gerais, São Paulo and Rio Grande do Sul were analysed. Twenty five aseptic leaf discs per sample were distributed in a moist chamber within a gerbox and incubated at 25 ºC and 12 hours photoperiod. After incubation for eight days the identification and quantification of the fungi incidence present in leaf discs were performed. In the 2008 season, there was a predominance of Drechslera siccans with an incidence of 0 to 75 %, being the first report of this species in wheat, Brazil. On the seasons average B. sorokiniana showed a 7.6 % incidence and 53.1 % frequency, D. tritici-repentis presented an incidence of 59.2 % and 90.6 % frequency, D. siccans incidence of 11.0 % and 48.1 % frequency, and S. nodorum with incidence and frequency of 1.55 % and 2.2 %, respectively.

Triticum aestivum; Drechslera; Bipolaris; Stagonospora


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