Indian mustard (Brassica juncea) commonly grown in rabi season (October-November), contribute 28.60% in total production of oilseed. The crop is prone to various diseases, amongst them Alternaria brassicae causing blight is more devastating in decreasing the production. It also affects of quality of seed by reducing its size, colour and oil content. Pathogen survives in infected plant debris throughout year stored at room temperature and refrigerated condition. Extract of Syperus rotundus and piper nigrum most effective in reducing the mycelia growth of fungus. Since use of fungicides, provide resistance against pathogens and pollute the environment, the efforts were made to identify the resistance inducing chemicals. For this, Isonicotinic acid and NAA @ 0.1% was found most effective in managing the disease.