Controle de mancha marrom em cevada com fungicidas sistêmicos associados ou não a multissítio e efeitos sobre a produtividade e a qualidade de sementes

Abstract

Barley is a crop of worldwide relevance, with several purposes, including use in malting. 32 The crop is subject to several diseases, including brown spot (Bipolaris sorokiniana), capable 33 of causing significant losses. The aim of this research was to evaluate the efficiency of the foliar 34 application of Qol, DMI and SDHI fungicides, associated with mancozeb, regarding the control 35 of brown spot, improvements in productivity and seed quality. The design was completely 36 randomized blocks (DBC) with four replications, consisting of five treatments: control, 37 pyraclostrobin + fluxapyroxad + epoxiconazole, propiconazole + phenpropimorph, 38 pyraclostrobin + fluxapyroxad + epoxiconazole + mancozeb, propiconazole + phenpropimorph 39 + mancozeb. The severity of brown spot was evaluated during the crop cycle, obtaining the 40 AUDPC and the disease daily increase ; after harvest, productivity and hectoliter weight were 41 measured, in addition to the germination capacity and incidence of the pathogen in the seeds 42 after 6 months of storage. It was observed that all treatments were efficient in reducing the 43 severity, AUDPC and disease daily increase, when compared to the control, which had an 44 impact on productivity, germination and incidence of the pathogen in the seeds. The most 45 efficient treatment in inoculum reducing in the seeds was T2, with an incidence of 8.25%, 46 against 57.5% of the control. Despite the importance of multisite fungicides in the management 47 of disease resistance, in this study no improvements were observed with the addition of 48 mancozeb on the variables studied.