Figure 4.

Benzoic acid and its hydroxylated derivatives, ρ-hydroxybenzoic acid (HBA) and protocatechuic acid (PCA), decrease the disease evaluation of early blight caused on tomatoes by Alternaria solani under greenhouse conditions. (A) Typical symptoms of early blight disease on tomato leaves at 7 days post-treatment (dpt) with 100 ppm of BA or one of its hydroxylated derivatives. (B) Disease progress curves of early blight disease on tomato leaves after the treatment with BA or one of its hydroxylated derivatives. (C) The area under disease progress curve (AUDPC) of early blight disease on tomato leaves after the treatment with BA or one of its hydroxylated derivatives. Values represent the means ± standard deviation (means ± SD) of six biological replicates (n = 6). Different letters indicate statistically significant differences between treatments (p < 0.05).