Intensidade da cercosporiose em mudas de cafeeiro em função de fontes e doses de silício

Abstract

The objective of this work was to evaluate the effect of calcium and sodium silicate on the intensity of brown eye spot (Cercospora coffeicola) in coffee (Coffea arabica) seedlings (Catuaí IAC 99) by using doses (0; 0.32; 0.63 and 1.26 g of SiO2 .kg-1) of substrate. Five evaluations were done by counting the number of diseased plants, number of leaves with lesions, number of lesions per leaf and total number of lesions per plant. The concentration of macro, micronutrients, silicon and lignin in the leaves was determined at the end of the experiment. The lowest area under the disease progress curve of the total number of lesions was observed with 0.84 g.kg-1 of sodium silicate. Diseased plants were found to have a linear decrease of area under the disease progress curve and an increase in the concentration of lignin up to the dose of 0.52 g.kg-1 of sodium silicate. The increase of sodium silicate and dose application into the soil up to 0.53 g.kg-1 decreased the concentration of SiO2 on the stem.