Studies detailed in this paper are not original research but a summary of the literature with microscopic and cultural studies intended to familiarize the writer with some of the more important fruit diseases. Material where available was brought into the laboratory and microscopic studies made of the host symptoms and causal organisms. Hesler and Whetzel's “Manual of Fruit Diseases," “The Plant Disease Reporter,” and “The Experiment Station Record" were found to be of much value in descriptive and reference work and "The Plant Disease Reporter” was considered authentic for nomenclature of the organisms. The pen and ink drawings accompanying each disease are diagrammatic representations and comparative magnifications are not given. / M.S.