The nature and magnitude of important nematode-induced diseases of crop plants are described in this book. The need to manage these diseases to achieve profitable crop production is stressed. Nematodes are found all over the world, but the principles and methods employed in managing them are essentially the same, regardless of location. A primary focus is placed on the types of damage nematodes cause to economic crops and how that damage affects yield and quality. A second emphasis the management tactics currently available and explains them in relation to the biology of specific nematodes. Advantages and limitation for each method are discussed. Environmental conditions influencing the extent of damage are also considered. Focus on characterizing the root-knot nematodes (Meloidogyne spp.), infection control in nematodes trapping fungus (D. brochopaga), and my selected crops in tomato. In writing certain chapters in this book, this information available for future use.