Management of Onion Leaf Blight by Alternaria alternata (FR.) Keissler by Botanicals and Bio-control Agents

摘要

Field experiment was carried out to assess the efficacy of plant oils, plant extracts and antagonistic microorganisms against leaf blight disease of onion caused by Alternaria alternata . Two sprays of neem oil (3%) given on onion plants at the first appearance of the disease and the second on 15 days later recorded significantly the lowest percent disease index (22.22%) and besides increasing the yield. In plant extracts Acorus calamus rhizome extract 10% was significantly reduced the disease incidence (34.78%) followed by Mentha arvensis leaf extract.