Rationale and concepts of crop loss assessment for improving pest management and crop protection. Measurement of disease and pathogens. Measurement of insect pest populations and injury. Modeling of crop growth and yield for loss assessment. Disease progress curves, their mathematical description and analysis to formulate predictors for loss equations. Sampling theory and protocol for insects. Methods of field data collection and recording in experiments and surveys. Generating the database for disease-loss modeling. Methods of generating different levels of disease epidemics in loss experiments. Methods of studying the relation between different insect population levels, damage and yield in experiments and surveys. Quantifying the relationship between disease intensity and yield loss. Quantifying the relationship between insect populations, damage, yield and economic thresholds. Empirical models for predicting yield loss caused by a single disease. Empirical models for predicting yield loss caused by one type of insect: the stem borers. The use of principal components analysis and cluster analysis in crop loss assessment. A mechanistic approach to yield loss assessment based on crop physiology. The systems approach to pest management. The concept of thresholds: warning, action and damage thresholds. The role of predictive systems in disease management. Economics of integrated pest control. Analysis of decision making in pest management. Pest surveiliance systems in the USA - a case study using the Michigan State crop monitoring system (CCMS). Crop loss assessment in a practical integrated pest control program for tropical Asian rice. A computer-based decision aid for managing bean rust. The siratac system for cotton pest management in Australia.