Efficiency of biological preparations against scab and powdery mildew of apple trees

Abstract

. Scab (caused by Venturia inaequalis Cooke (Wint.)) and powdery mildew (Podospaera leucotricha (Ellis & Everh. Salmon)) are harmful diseases of the apple tree, the protection against which is based on repeated spraying with chemical fungicides. To reduce the pesticide burden on agrocenoses, the use of biological protection products is relevant. The purpose of this study was to investigate the effectiveness of biological preparations based on fungi and bacteria (mycoparasites and antagonists) against scab and powdery mildew of apple trees. For this, a set of methods was used, including phytopathological diagnostics and disease monitoring, phenological observations, yield recording, and statistical analysis. The biological preparations Ampelomycin BT (6 l/ha) based on the fungus of the genus Ampelomyces Ces ex Shlecht., Gliocladin BT (10 l/ha), which contains mycelium and spores of the fungus of the genus Gliocladium, and Fluorescin BT (8 l/ha), which is based on bacteria of the genus Pseudomonas, were investigated. Their use led to a decrease in the spread and development of apple scab, and the technical efficiency of the preparations ranged from 68% to 79%. The biological preparations also reduced the damage to plants by the powdery mildew pathogen with a technical efficiency of 59-76%. Treatment of apple plants with Gliocladin BT, Ampelomycin BT, and Fluorescin BT reduced the number of scab-affected fruits by 22.7-35.6%. The technical effectiveness of the preparations was 62-78%. The use of the biological preparations under study ensured the preservation of the yield within 3.7-4.4 t/ha. The results obtained indicate the prospects of using biological preparations against scab and powdery mildew of apple trees for the ecologisation of plant protection