FIGURE 1.

Effects of Trichoderma strains against downy mildew. Direct effects of Trichoderma strains (A) were assessed on greenhouse‐grown grapevine plants, sprayed with water (control) and with a conidial suspension of T. asperellum T34 (T34), T. atroviride SC1 (SC1) or T. harzianum T39 (T39). Volatile‐mediated effects of Trichoderma strains (B) were assessed on grapevine leaf disks, treated with uninoculated potato dextrose agar (PDA) dishes (control) and dishes with PDA‐grown T34, SC1 or T39 colonies without contact with leaf tissues. Downy mildew severity was assessed at 6 days post inoculation. Five replicates were assessed for each treatment and each experiment was carried out twice. The Kruskal‐Wallis test indicated no significant differences between the two experimental repetitions (P > 0.05) and data from the two experiments were pooled. The pooled mean and standard error values of 10 replicates from the two experiments are presented for each treatment. Different letters indicate significant differences among treatments according to the Kruskal‐Wallis test (P ≤ 0.05)