In vivo and In vitro Management of Purple Blotch of Onion by Using Fungicides and Plant Extracts

An investigation was carried on the management of purple blotch disease of onion (Alternaria porri) during 2015-2016 at BARI, Joydebpur, Gazipur, Bangladesh to see the effectiveness of fungicides in controlling the disease and evaluate the performance of some plant extracts in controlling purple blotch disease of onion seed crop. In in vivo, the effectiveness of 10 fungicides (Antracol, Folicur, Iindofil M-45, Metaril, Rovral, Score, Sulcox, Sun copperoxy, Unilax and Vonot 306) were screen against the disease. The fungicides were applied at 0.2 %, three times at 10 days interval. Of them Rovral appeared the best followed by Score. Folicur, Antracol, Metaril, Sulcox and Indofil M-45. More or less similar trend of the fungicides became evident when they were tested against Alerternaria porri in in vitro. While fungitoxicity of seven plants extracts (Dhatura, Dholkolmi, Garlic, Ginger, Marigold, Neem and Nymbicidine) was tested in field condition. Nymbicidine showed significantly the best performance in reducing the disease incidence and giving higher yield.