Fig. 1

Root infestation evaluated at the end of the eight-week long treatment in well-watered and drought-stressed 5C and Riesling grafted on 5C grapevines (pooled data). Infestation intensity is classified as follows: 1 = presence of a low number of root nodosities (white stripes); 2 = 10 to 100 nodosities (light grey stripes); 3 = up to 200 nodosities (dark grey stripes); 4 > 200 nodosities (black stripes), presence of tuberosities on older lignified roots. Lettering denotes a statistically significant difference between groups (chi-square test)