Abstract: The effect of time of application of fungicide Dithane M-45 on black scruf disease and yield in potato was investigated. The fungicide was applied at the rate of 500 ppm two weeks before planting and two weeks after planting the potatoes. All the three were effective in reducing the disease when compared with the control. The fungicide application at the time of planting (T2) showed the lowest incidence (28.37%) and severity (2.71%) of the disease. However, fresh root weight, plant weight, plant height, number of tubers/plant, tuber size and yield were not significantly different in this than other treatments.