The book is a comprehensive and advanced textbook designed to provide in-depth knowledge of modern plant pathology diagnostics. The book systematically covers a wide range of detection techniques, starting from traditional visual symptom analysis to highly advanced molecular and artificial intelligence-based methods. It includes biochemical tests, microscopic techniques, cultural studies, serological assays, and nucleic acid-based methods such as PCR, qPCR, LAMP, and next-generation sequencing.The book also explores emerging technologies like biosensors, phage display, GC-MS, LC-MS, and flow cytometry for accurate pathogen identification. Special emphasis is given to modern innovations such as drone-based disease detection, machine learning, and deep learning applications in plant disease diagnosis.Aligned with current scientific advancements, the book integrates both phenotypic and genotypic approaches for precise identification of plant pathogens. It serves as a valuable resource for students, researchers, and professionals in plant pathology, agriculture, and biotechnology, supporting efficient disease management and sustainable crop protection strategies.