Efficacy of Fungicides, Botanicals and Bioagents Against Alternaria brassicae of Cauliflower

Alternaria leaf spot caused by A. brassicae (Berk.) Sacc. is one of the most wide spread, destructive disease of cauliflower (Brassica oleracea var. botrytis), which accounts for about 20–80 per cent yield losses. 1500, 2000 and 2500 ppm concentration of thirteen fungicides were tested in vitro against A. brassicae. All the treatment tested reported significant inhibition over untreated control. The average percentage mycelial growth inhibition recorded with all the systemic fungicides tested was ranged from 27.62% (Thiophanate methyl) to 100% (Hexaconazole). However, Hexaconazole were found highly fungistatic and recorded significantly highest average mycelial inhibition of 100 per cent, followed by Propiconazole (97.73%), Penconazole (95.04%), Difenconazole (94.27%) and Tebuconazole (90.09%). Whereas, fungicides Thiophanate methyl (27.62%) and Carbendazim (41.39%) were found less effective. Average percentage mycelial growth inhibition recorded with all non-systemic and contact fungicides tested at concentration 1500, 2000 and 2500 ppm was ranged from 76.23 (Cymoxanil 8%, Mancozeb 64%) to 90.24 (Carbendazim 25% + Mancozeb 50%). However, significantly highest percentage of mycelial growth inhibition was recorded with Carbendazim 25% + Mancozeb 50% (90.24%). This was followed by the fungicides viz., Mancozeb (85.3%), Carbendazim 12% + Mancozeb 63% (84.06%) and Copper oxychloride (78.32%). Fungicides Cymoxanil 8% Mancozeb 64% and Propineb were found comparatively less effective with less mycelial inhibition of 76.23 and 76.77 per cent, respectively. Bioagents viz., T. viride, T. harzianum and T. longibrachiatum recorded significantly highest inhibitions of 81.49, 76.50 and 73.97 per cent, respectively. Botanicals viz., A. sativum, A. indica and Z. officinale causes significantly highest mean mycelial inhibition of 85.62, 80.50 and 68.93 per cent, respectively.