Efficacy of Beltanol (SL 37.5%) on damping-off disease of cucumber

Damping-off disease caused by Phytophthora melonis is the most common disease of cucumber seedlings Cucumis sativus L.. To study the efficacy of 8-hydroxy quinoline sulfate (Beltanol®) in control of cucumber damping-off disease, glasshouse experiments were carried out with six treatments at research stations in Tehran, Alborz, and Semnan provinces in Iran. Treatments included 0.3, 0.4, and 0.5 ml∙l^-1 of Beltanol as the experimental fungicide, metalaxyl+mancozeb (Rosalaxyl® WP 72%; FRAC code 3 + M03) at 2 g∙l^-1 as the standard fungicide along with inoculated and untreated and non-inoculated (healthy) controls. Cucumbers were cultivated from seed in trays, and treatments were applied twice. Once after seed sowing and second time at the 2-leaf stage. Disease incidence was recorded at the 4-leaf stage. Beltanol at 0.3 ml∙l^-1 had the least effect among fungicides, with nearly 50% of treated plants showing signs of disease. Application of Beltanol at 0.4 and 0.5 ml∙l^-1 decreased disease incidence by 59.55 and 64.47% compared to the inoculated control, respectively. Rosalaxyl® performed better than Beltanol and reduced disease by 83.55%. However, to provide alternatives for proper fungicide rotations, Beltanol at the rate of 0.4 ml∙l^-1 may manage damping-off disease in cucumber.