Control of Cucumber Powdery Mildew Using Resistant Cultivars and Organic Agricultural Materials

This study evaluated the efficacy of various inorganic materials, biological control agents, organic agricultural materials (OAMs), and essential oils for controlling cucumber powdery mildew (CPM) under greenhouse conditions. Treatments included silicate, bicarbonate, copper sulfate, sulfur-based compounds, <i>Bacillus subtilis</i> KB-401, <i>Bacillus amyloliquefaciens</i> M27, Bordeaux mixtures, chitosan combined with oxidated copper salt, chitooligosaccharides, and essential oils such as castor and rapeseed oil with lecithin. Results demonstrated that Bordeaux mixtures, particularly Bordeaux Mixture I, and sulfur-based compounds provided the most reliable CPM control among inorganic materials. Bacillus strains KB-401 and M27 achieved sustained disease suppression, suggesting their value in integrated pest management (IPM). Chitosan combined with oxidated copper salt showed high efficacy, making it a promising candidate for long-term control. Among OAMs, loess-sulfur mixtures proved especially effective in preventive applications, achieving comparable results to resistant cultivar 'Saronsamcheok'. Essential oils, including castor and rapeseed oil, also exhibited significant CPM suppression potential, although repeated applications may be necessary for sustained control. These findings highlight the potential of these environmentally friendly treatments as viable components of an IPM strategy for managing CPM in cucumber crops. Further studies are recommended to optimize combinations and application timing for enhanced efficacy.