Incidence and management of severe mosaic of potato caused by PVY

Survey was conducted in five locations of Jorhat district of Assam viz Alengmara, Experimental farm of AAU, Kolbari, Teok and Titabar to determine the incidence of Potato virus Y (PVY) through symptomatology and presence of vector population and the detection of the virus by DAS-ELISA. Symptomatology revealed various degrees of mosaic, mild to severe mottling, distortion of leaves, leaf yellowing and reduction in leaf size. Out of the 321 tested leaf samples 109 samples were found to be positive for PVY showing a per cent infection of 33.95 per cent with highest per cent infection in Kolbari area (42.50%) having the highest mean ELISA value for all positive samples (0.286). In the field experiment for management of potato virus Y through integrated approach, it was evident that there was considerably low disease incidence with low vector population in the treatments of bio fumigation with rapeseed plants one month before planting (T4), followed by application of mineral oil @ 5 ml/lit at 15, 30, 45 and 60 days after transplanting (T2). The highest yield (105.98 q/ha) recorded for the treatment T4 with highest per cent reduction of disease over control and lowest vector population.