EFFECT OF FUNGICIDES AND BIO-BOTANICALS ON LESION DEVELOPMENT OF LATE AND EARLY BLIGHT OF POTATO IN FIELD CONDITIONRAHAMATULLA MIDDYA, SAIDUL ISLAM AND BHOLANATH MONDALAbstract Potato (Solanum tuberosum L., family Solanaceae) is an important cash crop throughout the world. The crop is suffering from number of diseases among which late and early blight of potato appear frequently in the field every year and cause maximum damage to the crop under West Bengal conditions. To minimize the diseases, field experiments were conducted at Benuria (Birbhum) during 2016-2017 under Red and Lateritic Agro-climatic Zone of West Bengal. The leaves of potato (cv. Kufri Jyoti) with typical late and early blight lesions were identified and tagged accordingly in the field. The total leaf area and initial lesion size of the selected leaves were measured using graph paper. The experiment was set up with RBD comprising of nine treatments and four replications. Suspension of different fungicides, biological agent and biobotanicals were prepared and applied at its field dose on the leaves with a hand sprayer. Expanded size was measured at every 4 days interval in both untreated and treated leaves. In late blight, the highest lesion expansion was observed in untreated control (71.77%) followed by Nimastra (65.89%) and Agneaastra (57.65%). It was significantly lower in Ethaboxam (3.41%) followed by FolioGold (9.69%) and Ishaan (10.73%). There was little variation between Indofil M-45 (25.20%) and Trichosol (25.63%). In case of early blight, increased size of the lesions measured after 4 days of spraying and it was highest in untreated control (60.02%) followed by Agneaastra (32.50%). Lesion expansion was significantly lower in Folio Gold (1.52%) followed by Ishaan (3.11%), Indofil M-45 (3.64%), Ethaboxam (6.20%) and Trichosol (6.82%). |