Management of Purple Blotch [alternaria Porri] Disease of Onion

The investigation was conducted at Department of Plant Pathology, Junagadh Agricultural University, Junagadh of Gujarat sate, India. where used differnt Agrochemicals and bioagents tested. Among systemic fungicides, hexaconazole were found to be the most effective fungicides and inhibited (99.6 %) per cent mycelial growth in vitro. Among non-systemic fungicides, mancozeb (83.5 %) and copper oxychloride (78.5 %) were quite effective. Among herbicides, pendimethalin and among insecticides profenofos were the best in vitro. Aqueous extracts of garlic (60.0 %) and turmeric (26.5 %) inhibited the mycelial growth of the fungus and extracts of mehandi also promising. The bulb yield increased in protected plots with Hexaconazole (0.005 %) over unprotected plots was 3.80 Kg/plot (94.06 per cent increase). Hexaconazole (0.005 %) was proved the best in controlling the disease in vivo resulting in higher bulb yield. T. viride-I (20x108 cfu/gm) was found most effective in vivo and resulting higher bulb yield. During the field survey maximum disease observed (17 to 70 %) at Mahuva taluka of Bhavanagar district and minimum disease observed (15 to 27 %) at Una taluka of Junagadh district.