Onion and garlic diseases harmly affect plant growth and bulb yield in field as well as quality and quantity during storage and transportation. Black mould, neck rot, blue mould etc are examples of these harms. Part one of the book cover the important diseases of onion and garlic caused by many organisms and non parasitic diseases. Part two include management of this diseases with different control methods, being adopted world-wide and the important procedures when storing onion and garlic. This guide is directed to growers, agricultural engineers and students.