The book is highly beneficial to the undergraduate and post graduate students of Botany, Agriculture & Horticulture and of most of the universities of the world. The reason to write such a book is to provide knowledge of basic concepts and emerging facts of the plant diseases of economically important crop plants. For the preparation of this book we have taken help of many research journals, bulletins and periodicals of concern subject. Most of the diseases of major importance for 30 different crop plants of economically important at world level presented through this ext. The book is of great immense to researchers, students and farmers in formulation of computer based disease forecasting system for forecasting the information of diseases about their intensity, status, identification of causal organisms, control and eradication of particular diseases in the particular area. The book will be useful to plant pathologist in plant disease clinics in identification of diseases of crop.