The book deals with biological control of Pythium aphanidermatum causing damping-off disease of mustard by Trichoderma species. Damping-off disease of mustard occurs worldwide resulting in great loss to this crop. Trichoderma species have been widely exploited for plant growth promotion as well as in biological control of plant pathogens. Chemical fungicides are the main commercially available option for control of the disease. However, fungicides no more remain as an option for plant disease control due to their poisonous nature. Therefore, biological control is an attractive alternative. Our future agriculture must be based on organic farming where Trichoderma species are the most favored ones. They are omnipresent in agricultural and natural soils throughout the world and have a rapid growth rate, persistent conidia and a broad spectrum of substrate utilization that makes them very efficient in the competition for nutrients and living space. The book will be of great value for researchers as well as for people of industry.