Manejo da ferrugem da folha (Puccinia coronata f. sp. avenae) na cultura da aveia (Avena sativa) com fungicidas microbiológicos e ácido silícico

Abstract

White oat is an important winter crop in Southern Brazil, and leaf rust, caused by Puccinia coronata f. sp. avenae, is its main disease, with the potential to cause yield losses of up to 50% in susceptible cultivars. This study aimed to evaluate the effect of microbiological fungicides and silicic acid on the management of leaf rust and on yield components of white oat. Two field experiments were conducted using the cultivar IPR Artemis. The experimental design was a randomized complete block design in a split-plot arrangement, with the presence or absence of silicic acid as the main factor and five microbiological fungicides plus a control as the secondary factor. The variables evaluated were disease severity, area under the disease progress curve, plant height, stem diameter, number of tillers, number of panicles, number of spikelets in the main panicle, thousand-grain weight, and grain yield. Silicic acid application reduced leaf rust severity by 14%. Trichodermil® and Bio-imune® reduced disease severity by 20.8% and 20.3%, respectively, compared with the control, while the association of Pardella® with silicic acid reduced the area under the disease progress curve by 17.5%. The association of Trichodermil® with silicic acid increased thousand-grain weight by 21%, although it reduced plant height and the number of spikelets in the main panicle. The use of Trichodermil® also reduced stem diameter. Grain yield was not affected by the evaluated treatments. It was concluded that silicic acid and microbiological fungicides have potential for the management of white oat leaf rust; however, they did not promote increases in grain yield under the conditions of this study.