Phytoplasmas are the plant pathogenic bacteria that cause plant health problems around the world. Our knowledge about these important plant pathogens has advanced rapidly over the last decade as their impact on major agricultural and horticultural crops and ornamental plants has risen. This comprehensive volume by leaders in the field or phytoplasmology brings together current research on phytoplasmas, their plant hosts and insect vectors. The various approaches to differentiation, classifications and taxonomy are examined in detail, including genome sequencing and functional genomics. Discussions of the relationship between phytoplasmas and plants include the development of disease, biochemical changes in their plant hosts, plant resistance and epidemiology of disease. Finally, transmission by insect vectors, their control and the distribution and potential spread of phytoplasma diseases and vectors are considered. This book will be a valuable reference for researchers and upper-level students in crop protection, plant pathology and applied entomology.