Control of soybean anthracnosis with potassium leaf applicattion

Abstract

The maintenance of the plants' productive potential could be guaranteed through disease management. The objective of the experiment was to evaluate a foliar application of potassium in reducing the severity of soybean anthracnose. Two potassium sources were evaluated: Potassium Silicate and Potassium Chloride, and five doses, in two soybean cultivars (M6410 IPRO; NS6700 IPRO). Two sources of Potassium were evaluated: K2SiO3 (Quimifol Silicon 131 g.L-1 of K2O) and Potassium Chloride (KCl P.A. 99.5%) at doses 0; 1.31; 2.62 1; 5.24; 10.48 g L-1 in K2O equivalent. Phytotoxicity was evaluated at seven days after inoculation, severity on a grading scale at 7 and 12 days after inoculation and an area of disease at 12 days. The phytotoxicity and severity score variables were submitted to Kruskal-Wallis and Dunn 5% analysis and a variable area of the disease was submitted to ANOVA. Thus, for significant hospitalization among those adopted, polynomial regression equations were adjusted for each K source applied to each cultivar. The use of K2O, having potassium silicate and potassium chloride as sources, informed via the leaves, induces the severity of anthracnose in soybean cultivars, however, high doses of phytotoxicity in the plants.