Contents: 1. Introductory. 2. History of phytopathology. 3. Plant pathogens. 4. Variation in plant pathogens. 5. Pathogenicity, infection and disease development. 6. Plant pathogen in offence. 7. Host plant in defence. 8. Genetical aspects of host pathogen interaction. 9. Physiological, cellular and molecular changes in diseased plants. 10. Environment and nutrition in relation to disease development. 11. Epidemiology. 12. Postharvest diseases of fruits and vegetables. 13. Principles and methods of plant disease control. 14. Biotechnology in relation to plant pathology. 15. Plant diseases caused by fungi. 16. Plant diseases caused by bacteria. 17. Plant diseases caused by viruses. 18. Plant diseases caused by mycoplasma like organisms. 19. Plant diseases caused by phanerogamic parasites. 20. Plant disease caused by nematodes. 21. Non-parasitic diseases. 22. Glossary.