The course deals with molecular mechanisms of pathogenesis of plant pathogens; Molecular biology of host parasite interaction and biochemical mechanisms of pathogenesis; Molecular mechanisms and approaches to manage plant pathogens. It provides and gives basic molecular plant pathology knowledge and skill to students on the biology of host pathogen interaction and its application at molecular level. It also deals with the historical development of plant pathology; host pathogen interaction (Fungi, bacteria, viruses and mycoplasma); physiological changes in diseased plants; primary disease determinant, toxins; mechanism of resistance, gene deployment; phytoalexins, microbial interactions, antibiotics; fungal enzymes and their action; post-transcriptional gene silencing (PTGS); pathogen derived toxins, systemic resistance and mechanisms of hypersensitive reactions (HR). The course also covers application of molecular techniques in plant disease management, molecular disease diagnostics, the use of nucleic acid based techniques, and application of molecular biology in identification of resistance genes. It provides basic knowledge and techniques on principles, methods, mechanism of bio-control agents, fungicides and their use against plant pathogens.