Evaluation of Biocontrol Agents and Fungicides against Alternaria Leaf Spot of Spinach

Background: Spinach (Spinacia oleracea) is a worldwide cultivated crop and is attacked by a complex of foliar diseases. Alternaria leaf spot has become quite a problem as it results in poor quality and low yield. Methods: The experiment was conducted during 2021-22 with a total of four fungicides viz Carbendazim 12% + Mancozeb 63% WP, Hexaconazole 5% SC, Azoxystrobin 18.2% + Difenoconazole 12.5% W/V, Copper oxychloride 50% and three bio-control agents viz. Trichoderma viride, Trichoderma asperellum, Trichoderma harzianum to evaluate their effectiveness against Alternaria leaf spot of spinach. Fungicides were evaluated at four concentrations viz 25, 50, 75 and 100 ppm for their efficacy. Result: All the tested chemicals and bioagents were effective to reduce the disease severity, but hexaconazole at 100 ppm was the most effective in controlling the radial growth (82.55% inhibition) followed by Azoxystrobin (79.97%). The study established the efficacy of fungicides and bio-agents against Alternaria leaf spot of spinach caused by Alternaria alternata. The levels of inhibition revealed the potential to manage pathogen and can be used for better yield and good quality product thereby minimizing risks of crop failures.
