This book ¿Eco-friendly Management of Alternaria Blight Disease of Mustard¿ is the outcome of fourteen years research experience in Plant Pathology. This book has been written for the eco-friendly management of most destructive alternaria blight disease of mustard. These eco-friendly non-conventional chemicals provide nutrients to the host plant which affect the relationship between crop and pathogen in many ways. By applying the chemicals, host plant induces resistance to the pathogens by induction of host resistance, such as salicylic acid or methyl jasmonate. Efforts have been made to manage the disease by using appropriate doses of such host resistance inducer chemicals. Manipulation of crop nutrition gives the farmer a valuable tool for managing crop health as well as reduced public pressure over pesticide residue in food and in the environment.