Silicato de potássio aplicado via foliar e a incidência da brusone em arroz

Abstract

Silicon (Si) is now recognized as a beneficial element for the plants. The direct and indirect benefits of the element for the cultures (mainly grasses) are related to tolerance to diseases, pests and to water stresses. As most of these studies were done with fertilizers applied to the soil, studies related to the efficiency of the plants in absorbing Si through the leaves are necessary. The study of the absorption of Si through the leaves in blast incidence (Pyricularia oryzae), was done in an experiment using potassium silicate (K2SiO3) in different doses (0, 1, 2, 4, 8 and 16 g L-1 Si), number of applications and variation of the pH of the tank mixture. For such, rice (Oryza sativa) was cultivated in rots (cultivar Metica 1 - susceptible to blast), in a completely randomized design. Silicate was applied starting from the 22nd day after seedling emergence (DAE). The pathogen (P. oryzae) was inoculated on the 25th DAE. Disease incidence was evaluated ten days after the inoculation. The foliar application of potassium silicate did not increase the absorption and accumulation of Si in the aboveground parts of the plant; however, there was a decrease in blast incidence. The best Si dose for blast incidence reductor was 4 g L-1, independent of the solution pH. There were no differences among the number of times in that 4 g L-1 Si was applied.