Management of Alternaria Leaf Spot and Blight of Radish

Leaf spot and blight caused by Alternaria spp. is on of the most important disease of Brassica species through out the world, which often results in severe yield losses. It is considered as a number one disease of radish affecting both fresh vegetable and seed production. The disease is more severe when the plants are left for seed production in the field and causes significant reduction in seed yield. Experiments were conducted to find out the efficacy of biological and botanical extracts against the Alternaria leaf spot and blight disease of radish in Rampur, Chitwan during 2008-2009. Nine different treatments were tested by poisoned food technique in the laboratory. They were further tested by seed treatment and foliar spray on radish plant in the field. In vitro test indicated that all the treatments were highly significant in controlling the pathogen over control. Lemon grass oil and mancozeb were the most effective (100% inhibition) followed by garlic extract and cattle urine.The results revealed that seed treatment with lemon grass oil and foliar spray with garlic extract could be the option for management of Alternaria leaf spot and blight for radish seed production.