The objective of this work was to assess the influence of foliar application of resistance inducers and the activation of plant pathogenesis-related (PR) proteins, chitinases and beta-1,3-glucanases, against Xanthomonas campestris pv. vesicatoria, and evaluate the potential of these elicitors on the reduction of bacterial leaf spot. Tomato plants of the cultivar Santa Cruz Kada were sprayed with: acibenzolar-S-methyl (0.2 g L-1 ASM); Ecolife, a biological formulation based on citric biomass (5 mL L-1); chitosan suspension from Crinipellis perniciosa mycelium (MCp; 200 g L-1); an aqueous extract from branches of lobeira (Solanum lycocarpum) infected with C. perniciosa (VLA; 300 g L-1). Plants were challenged with a virulent bacterial strain four days after spraying. Plants sprayed with the tested substances showed reduction of bacterial spot. ASM provided 49.3% protection, and was equal to MCp and Ecolife, and superior to VLA. VLA treatment did not differ statistically from MCp and Ecolife. Increases of beta-1,3-glucanase and chitinase activities were observed in treated plants at the first hour after spraying.
Solanum lycocarpum; Xanthomonas campestris; acibenzolar-S-methyl; biological extracts; induced resistance
