The influence of fungicides and plant growth regulators on the susceptibility of apple trees (

The study was conducted during the 2024-2025 growing seasons on the territory of the Fruit Crops Department of the V.I. Edelstein Educational, Scientific and Production Center for Horticulture and Vegetable Growing of the Russian State Agrarian University - Moscow Timiryazev Agricultural Academy in Moscow. The experiment was laid out in three summer plantings of the Rozhdestvenskoye and Honey Crisp apple varieties. The field experiment included treatments with the fungicides Skor, KE (250 g / l difenoconazole), Horus, VDG (750 g / kg cyprodinil), as well as options with separate use of plant growth regulators Obereg, P (0.15 g / l arachidonic acid), AgroStimul, VE (50 g / l dihydroquercetin). During the growing season, the biological effectiveness of the treatments in reducing fungal diseases (powdery mildew and Alternaria blight) and their impact on apple shoot growth were assessed. It was found that the combined use of these growth regulators and fungicides resulted in the best results in reducing fungal disease development and increasing apple shoot growth throughout the growing season. Over the course of two years of research, it was found that the separate use of these growth regulators also significantly reduced the development of fungal diseases and contributed to increased shoot growth in the current year compared to the control.