This study aimed to test the efficiency of different molecules on the reduction of the relative lesion extension (RLE) of sheath blight in rice. Plants of cultivars BR-Irga 409 and Labelle were grown in nutrient solution and inoculated with Rhizoctonia solani at the maximum tillering stage. At 24 hours before inoculation, sheaths of plants were sprayed with solutions of potassium silicate (PS), potassium silicate + phosphorus (PS+P), Acibenzolar-S-Methyl (ASM), Carbendazim fungicide, deacetylated chitosan (DC), ethylene (ET) and potassium phosphite (PP). Sheaths from plants sprayed with water served as the control treatment. The effect of these products on R. solani mycelia growth was also studied in vitro. For BR-Irga 409, the RLE was lower with the application of PP compared with the other treatments, except the Carbendazim. The application of Carbendazim reduced in 86.1% the RLE in comparison with the control. The RLE was lower for BR-Irga 409 than for Labell with the application of PP. Mycelia growth of R. solani was inhibited only by PP and Carbendazim in comparison with the other treatments. There was no significant difference among the treatments control, PS, and PS+P for silicon concentration on sheaths of plants of the two cultivars.
induced resistance; inducers; Oryza sativa; Rhizoctonia solani; silicates
