Potassium silicate as foliar spray and rice blast control

Silicon (Si) is known as a "beneficial element" for plants. The direct and indirect benefits of the element for crops (especially grasses) are related to resistance to diseases, pests, and drought. Since most studies were done with fertilizers applied to the soil, new studies on the efficacy of silicon absorption through the leaves are required. The effect of silicon absorption through the leaves on rice blast (Pyricularia oryzae) control was studied using potassium silicate (K2SiO3) in different doses (0, 1, 2, 4, 8, or 16 g L-1 Si), number of sprayings at two solution pHs. Rice (Oryza sativa), cultivar 'Metica 1' (susceptible to blast), was grown in pots in a completely randomized experimental design. Silicate was applied beginning at the 22nd day after emergence (DAE). The pathogen was inoculated on the 25th DAE. Disease incidence was evaluated ten days after inoculation. Potassium silicate pulverization on the leaves did not increase Si absorption or accumulation by the plant; however, there was a reduction on blast incidence. The greatest reduction on blast incidence was observed at 4 g Si L-1, regardless of solution pH.