Application of AQ-10 biofungicide on Quercus robur L. seedlings.

Powdery mildew on oak is caused by the fungus Microsphaera alphitoides. AQ-10, a new biofungicide that contains fungal spores of Ampelomyces qisqualis Ces. ex Schlechtend, was used for biological control of powdery mildew on oak. The efficacy of AQ-10 has been reported to increase with the addition of polymers. Experiments were carried out in the nursery “Rogot” on seedlings of 6 years old Q. robur L. oaks. The trials were set according to instructions of methods PP1/152 (2) and PP1/69 (2), and treatment plan was made according to a fully randomized block design. The experiment was conducted in four repetitions. The basic plot had an area of 25 m and consisted of 8 trees (1x3 m apart). Phytotoxicity was estimated by PP methods 1/135 (2), the intensity of infection according to Towsend-Heuberger, the efficiency by Abbott, the analysis of variance with Duncan test and PP/181 (2). When AQ10 was used in doses of 30 g/ha, infection rate was 15.35%, while the efficacy was 48.05%. The application of medium and highest doses (50 g/ha and 70 g/ha) brought the efficacy up to 75.80 and 79.19%. On the untreated variants, percentage of infection was 29.55%. When AQ-10 was applied in combination with polymer Nu Film 17, all variations in all combinations showed a satisfactory efficacy of 84.26-92.89%, and a low infection rate of 4.65-2.10%. The fungicide Sulfur SC showed an efficiency of 84.43%, and AQ-10, in combination with Nu Film P, also demonstrated a good efficiency range of 73.60-94.59%.