In vitro Study on Fungicide Sensitivity of Alternaria brassicicola for Managing Leaf Blight in Mustard (Brassica juncea)

Alternaria brassicicola, a phytopathogenic fungus, incites Alternaria leaf blight in mustard, leading to substantial yield and quality losses. This study aimed to investigate the efficacy of seven chemical fungicides against A. brassicicola in vitro. Seven chemical fungicides were assessed at 50, 100, 250, and 500 ppm concentrations using the poisoned food technique and Completely Randomized Design (CRD). Tebuconazole + Trifloxystrobin and Tebuconazole exhibited 100 per cent growth inhibition at 100-500 ppm. Mancozeb + Metalaxyl and Mancozeb demonstrated 100% growth inhibition at 250-500 ppm. Chlorothalanil displayed 83.33% growth inhibition at 500 ppm, while Thiophanate methyl showed the least efficacy (48.00% growth inhibition) at 50 ppm. The findings suggest that Tebuconazole-based fungicides are highly effective against A. brassicicola. Lower concentrations (50-100 ppm) of certain fungicides also exhibited promising results.