The manual summarizes the main diseases of tree and shrub species (including those used for greening cities), their pathogens and abiotic factors, making forecasts of diseases of tree and shrub species, plant immunity, methods of protection against diseases and their prevention. The manual is based on the experience of teaching phytopathology at the Faculty of Forestry of St. Petersburg State Medical University. Intended for students of higher educational institutions studying in the direction of training 250100 "Forestry."