The monograph summarizes global experiences and provides the author's personal conclusions, incorporating theoretical generalizations about the spread of Alternaria blight, potato growing technology, and crop protection. The areas affected by the disease in the south-western Forest Steppe of Ukraine are highlighted. The express methods for determining potato variety resistance against Alternaria blight are introduced. Aspects of the usage of biological preparations and the observation of their possible combinations for active stimulation are discussed in this work.The book is recommended for plant pathologists, scientists, plant protection specialists, students in agricultural higher education specializing in Plant Protection and Quarantine, as well as specialists in agricultural enterprises and farmers.