Figure 2

Disease incidence (mean % of plants with visible symptoms) on grapevine cuttings treated with thiamine (solid bars) or water (white bars). Grapevine plants grown under glasshouse, controlled conditions were treated with water (control) or 30 mM thiamine and the abaxial leaf surfaces were inoculated with a sporangial suspension at 5 × 10⁴ sporangia/ml. Disease incidence was assessed 7 dpi as proportion of plants showing necrosis, oil spots, and sporulation symptoms [20]. Six plants were used per treatment and the experiment was repeated 3 times. All figures in thiamine treatments are significantly different at 5% level from the controls.