Inhaltsangabe1 Inoculum.- 1.1 Role of Inoculum in Root Disease Epidemics.- 1.1.1 Concepts of Inoculum.- 1.1.2 Soil Fungistasis.- 1.1.3 Inoculum Potential.- 1.1.4 Inoculum Efficiency.- 1.1.5 Inoculum Density.- 1.1.6 Spheres of Influence on Inoculum.- 1.2 Forms of Inoculum.- 1.2.1 Primary Inoculum.- 1.2.2 Secondary Inoculum.- 1.3 Survival of Inoculum.- 1.3.1 Idealized Survival Curve.- 1.3.2 Transformation of Survival Curves.- 1.4 Quantifying Inoculum in Soil.- 1.4.1 Direct Counts.- 1.4.2 Bioassays.- 1.4.3 Soil Assays.- 1.4.4 Chemical Assays.- 1.4.5 Serological Assays.- 1.5 Inoculum Density-Disease Relationships.- 1.5.1 Inoculum Density-Infection Court Relations.- 1.5.2 Transformation of Inoculum Density-Disease Curves.- 1.5.3 Usefulness of Transformed Inoculum Density-Disease Curves.- 1.5.4 Probability Models for Inoculum Density-Disease Relations.- 1.6 Concluding Remarks.- References.- 2 Host Roots.- 2.1 Introduction.- 2.2 Root Growth and Energy Availability.- 2.2.1 Specific Tissue Contributions.- 2.2.2 Characterization of Relevant Root Tissues.- 2.3 Root System Plasticity.- 2.3.1 Conceptual Frameworks for Root System Structure.- 2.4 Evaluation of Root Systems.- 2.5 Host Susceptibility.- 2.5.1 Host Influences on Susceptibility Alterations.- 2.5.2 Environmental and Cultural Factors in Susceptibility Alterations.- 2.6 Measuring Susceptibility Alterations.- 2.7 The Future.- References.- 3 Mycorrhizae.- 3.1 Distribution and Ecological Impact of the Mycorrhizal Symbiosis.- 3.2 Productivity of Cultivated Mycorrhizal Plants.- 3.3 Mycorrhizae - Root Disease Relationships.- 3.3.1 Mechanisms Decreasing the Impact of Soilborne Pathogens in Mycorrhizal Root Systems.- 3.3.1.1 Direct Interactions of Mycorrhizae and Soilborne Pathogens.- 3.3.1.2 Indirect Interaction of Mycorrhizae and Soilborne Pathogens.- 3.3.2 Role of Mycorrhizal Fungi as Biocontrol Organisms - Significance of the Known Biological Effects in Practical Plant Production.- 3.3.3 Mycorrhizae in Integrated Plant Production.- 3.4 Future Research.- References.- 4 The Soil Environment.- 4.1 Introduction.- 4.2 Components of the Physical Soil Environment.- 4.2.1 The Soil Matrix.- 4.2.2 The Soil Solution.- 4.2.3 The Soil Atmosphere.- 4.2.4 Soil Temperature.- 4.3 Influence of Edaphic Factors on Roots and Pathogens.- 4.3.1 Root Growth and Spatial Arrangement.- 4.3.1.1 Soil Matrix Effects.- 4.3.1.2 Soil Solution and Atmosphere Effects.- 4.3.1.3 Epidemiological Significance of Altered Root Growth.- 4.3.2 Pathogen Activity.- 4.3.2.1 Soil Matrix Effects.- 4.3.2.2 Soil Solution and Atmosphere Effects.- 4.3.2.3 Soil Temperature Effects.- 4.3.3 Host Disposition.- 4.3.3.1 Soil Solution and Atmosphere.- 4.3.3.2 Soil Temperature Effects.- 4.3.3.3 Mechanism of Predisposition.- 4.4 Conclusions.- References.- 5 Estimating Disease Severity and Incidence.- 5.1 Role of Disease Assessment in Root Disease Epidemiology.- 5.1.1 The Need for Disease Assessment.- 5.1.2 Goals of Disease Assessment.- 5.2 Signs and Symptoms.- 5.3 Root and Shoot Symptoms.- 5.3.1 Physiological Relationships.- 5.3.2 Environmental Effects.- 5.3.3 Temporal Aspects.- 5.4 Disease Assessment.- 5.4.1 Illusions and Hazards of Disease Assessment.- 5.4.2 Methodology.- 5.4.2.1 Visual Estimates.- 5.4.2.2 Electronic Techniques.- 5.5 Sampling Considerations.- 5.5.1 Sampling Pattern.- 5.5.2 Sample Numbers and Costs.- 5.6 Recommendations.- References.- 6 Temporal Aspects of the Development of Root Disease Epidemics.- 6.1 The Shapes of Disease Progress Curves.- 6.2 The Dynamics of Infection and Disease.- 6.2.1 Primary Infection.- 6.2.1.1 Infection of Plants from a Large Reservoir of Inoculum in Soil.- 6.2.1.2 Root Growth and Decay of Inoculum.- 6.2.2 Secondary Infection.- 6.2.2.1 Root-to-Root Spread.- 6.2.3 Linking Primary and Secondary Infection with Allowance for Root and Inoculum Dynamics.- 6.2.3.1 Growth Equations.- 6.2.3.2 Computer Simulation: An Alternative Approach.- 6.2.4 The Death of Roots, Latent and Infectious Periods.- 6.2.5 Antagonistic Interacti