Class lectures describe the classical and modern techniques that are used to diagnose and quantify plant diseases in farmer fields as well as under controlled environments . The main techniques include disease symptom and sign-based diagnostics, enzyme-linked immunosorbent assay (ELISA), microscopic examinations, nucleic acid (DNA/RNA) based detection and next-generation sequencing. Students are required to submit a term paper at the end of the course. The course involves critical discussion on the application of techniques, methodology, data collection, and analysis. Dual-listing: PPTH 448.