Fig. 1. Flow chart of the experiment

Fig. 2. Healthy leaves and inoculated leaves with disease spots at 6 DPI
(a): Heathy leaf; (b): Leaf with scattered lesions; (c): Leaf covered with lesions

Fig. 3. Chlorophyll fluorescence imaging system

Fig. 4. Chlorophyll fluorescence measurement procedure

Fig. 5. Flow chart of feature selection algorithm (SFFS) and model construction

Fig. 6. PCR values of healthy and inoculated samples measured 6 consecutive days after inoculation

Fig. 7. Representative kinetic chlorophyll fluorescence curves of healthy and inoculated leaves
(a): 1 DPI; (b): 2 DPI; (c): 6 DPI

Fig. 8. RGB and chlorophyll fluorescence parameter images of leaves inoculated with Plasmopara viticola

Fig. 9. Means and standard deviations of chlorophyll fluorescence parameters of grape leaves healthy and inoculated with downy mildew for 6 consecutive days (statistically significant differences are indicated)
*p<0.05; **p<0.01; ***p<0.001