FIGURE 6.

Mean B. lactucae conidia counts were reduced in lettuce (L. sativa) leaves infiltrated with a 2.5-fold increase in quercetin 3-O-(6-O-malonyl)-b-D-glucoside compared to mock infiltrated leaves in cultivars El Dorado and Salinas (n = 14–52). Lettuce plants were grown to 17 days old and then the oldest true leaf infiltrated with water (mock) or quercetin 3-O-(6-O-malonyl)-b-D-glucoside using a needleless syringe to reach a 1. 5-, 2. 5-, or 4-fold increase compared to a standard crisphead-type lettuce plant. Control plants were not infiltrated. Plants were then inoculated with 10⁵ conidia mL^{– 1} of B. lactucae. At 12 days post-inoculation, the infiltrated leaf was washed in water and the resulting conidia suspension counted. Error bars are 1 SE. Letters indicated significance groupings within each cultivar (ANOVA Tukey HSD; p < 0.05).