author(s)
Susmita Jha, Surajit Khalko, Abhijith M, PM Bhattacharya and Ayon Roy

abstract
Late blight of potato caused by Phytophthora infestans (Mont.) de Bary is one of the most devastative diseases of agricultural crops. Measures for managing the disease is based on chemicals but these are hazards to environment, development of resistance in pathogen against fungicides increased needs integrated approach of managing disease. So along with chemical management practices other measures of disease management should be studied. In cultural management practices, fertilization plays an important role. Nitrogen being an essential constituent of protein and chlorophyll is important for growth and development of plants as well as yield. So in greed of more yield higher dose of nitrogen application is in practice. But nitrogen has both direct and indirect effect on plant making it susceptible to the pathogen. Direct effect is increased succulence of plant tissue so increased susceptibility. Indirect effects are bigger canopy which alters micro-climate of plant making it favourable for disease establishment and increases the spread of pathogen. So the optimum dose of nitrogen which can provide higher yield and should not make plant susceptible to the pathogen should be estimated. This study includes study of effect of different regimes of nitrogen on Late blight of potato. There were 6 doses of nitrogen ranging from 0 to 250 kg/ha out of which 150 kg/ha was found to be most suitable in terms of yield as well as less disease severity.