Plant Diseases: Epidemics and Control provides a description of the methods of epidemiological analysis based on infection rates and the relation between the amount of inoculum and the amount of disease it produces. The book shows how to study the increase of pathogen populations and the epidemiological strategy to be adopted to control the epidemic of plant diseases. The text covers the calculation of the logarithmic increase of disease; use of epidemiology in the study of control; forms of sanitation; the use of resistant plant varieties; and the design of field experiments. Plant pathologists and breeders, agriculturists, horticulturists, research workers, teachers, and students will find the text invaluable.
Inhalt
Contents
Preface
Chapter 1 The Control of Plant Disease Studied as Part of Epidemiology
1.1. The Population of Pathogens
1.2. Epidemics and Biological Warfare
1.3. The Language of Epidemiology. Some Expressions
1.4. A Suggested Order of Reading the Chapters
1.5. The Spread of Disease and Its Bearing on the Technique of Field Experiments
Chapter 2 About Interest on Money. Logarithmic Increase
Summary
2.1. Interest is Proportional to Initial Capital
2.2. Interest per Cent and Interest per Unit
2.3. Simple Interest
2.4. Discontinuous Compound Interest
2.5. Continuous Compound Interest
2.6. Continuous Compound Interest Seen in Another Way
2.7. Equivalent Rates of Continuous and Discontinuous Compound Interest
2.8. Variable Rates of Continuous Compound Interest
2.9. Consistent Units of Time
2.10. Natural Logarithms
2.11. Logarithmic Increase
Exercises
Chapter 3 The Logarithmic and the Apparent Infection Rates
Summary
3.1. Statement of the General Problem of This Book
3.2. The Intermittent Increase of Disease
3.3. The Percentage and the Proportion of Disease
3.4. Logarithmic Increase of Disease and Increase That Is Not Logarithmic
3.5. The Meaning of Infection Rates
3.6. The Words, "per Unit," Again
Exercises
Chapter 4 How to Plot the Progress of an Epidemic
Summary
4.1. The Increase of Disease with Time
4.2. Two Ways in Which Disease Can Increase with Time."Compound Interest Disease'* and "Simple Interest Disease"
4.3. Increase of Disease by Multiplication. "Compound Interest Disease"
4.4. The Increase of Disease without Multiplication. "Simple Interest Disease"
4.5. The Correction Factor (l - x)
4.6. The Reason for Using Log [1/(1 - x)] When There is No Multiplication
Exercises
Epilogue
Chapter 5 The Basic Infection Rate
Summary
5.1. The Basic Infection Rate and the Latent Period
5.2. The Incubation Period
5.3. Some Biological Meanings
5.4. The Early Stages of Artificially Induced Epidemics of Stem Rust of Wheat
5.5. The Relation between r and R
5.6. How R Changes as an Epidemic Progresses
5.7. The Relation between r1 and R
5.8. The Products pr1, pr, and pR
5.9. The Limit to the Explosiveness of an Epidemic
5.10. A Discontinuous Infection Model
5.11. Period of Infection is Reduced to a Point Each Year and p is 1 Year
Exercises
Chapter 6 The Latent Period
Summary 59
6.1. Logarithmic Increase of Infection with p and R Constant
6.2. The Variation of n with Time, with p and R Constant
6.3. The Variation of r{ at an Average Value over an Interval of Time
6.4. The Effect of a Prolonged Period of Inoculation on the Variation of r1
6.5. The Effect of Variation of the Latent Period p on the Variation of r1
6.6. A Wider Interpretation of r1
6.7. The Error from Using a Constant Mean Value p in Eq. (5.7) Instead of a Constant Value p
6.8. Increase of Infection beyond the Logarithmic Phase with p and R Constant
6.9. The Estimation of n after the Logarithmic Stage of an Epidemic
6.10. Three Arbitrary Stages in an Epidemic
Exercise
Chapter 7 Average Values of Infection Rates. Increase of Populations of Lesions and of Foci. Independent Action of Propagules
Summary
7.1. The Relative Infection Rate as an Average
7.2. The Logarithmic Infection Rate
7.3. The Growth of an Individual Lesion in Relation to the Growth of a Population of Lesions
7.4. The Growth of Foci
7.5. The Spread of Pathogens in Relation to the Focal Pattern
7.6. The Growth of an Individual Focus in Relation to the Growth of a Population of Foci
7.7. The Mass Increase of Foci
7.8. Massed Foci of Potato Blight. The Epidemic S
7.9. The Independent Action of Propagules. The General Problem
7.10. The Independent Action of Propagules. Puccinia graminis. Phytophthora infestons, and Some Other Pathogens
Chapter 8 Corrected Infection Rates
Summary
8.1. Correction of n and r for the Growth of the Host Plants
8.2. Correction for Removals
8.3. Relation between the Corrected Basic Infection Rate Re and r
8.4. Balance in Epidemics
8.5. Relation between Rc and r1
8.6. A Threshold Theorem
8.7. The Threshold Theorem and Control of Disease by Fungicides
8.8. The Threshold in Epidemics of Two Systemic Diseases
8.9. Looking Back
Exercises and Examples
Chapter 9 Stochastic Methods in Epidemiology
Summary
9.1. Transforming Proportions of Disease
9.2. Sampling Errors of Estimates of Infection Rates
9.3. Deterministic and Probability Methods in Epidemiology
9.4. Multiple Infections with Systemic Disease
9.5. The Overlapping of Local Lesions
9.6. The Influence of Numbers
9.7. Comparisons with Medical Epidemiology
Chapter 10 A Guide to the Chapters on Control of Disease
10.1. The General Proposition
10.2. Control Measures That Reduce xo: Sanitation, Vertical Resistance, and Chemical Eradication
10.3. Control Measures That Reduce r: Horizontal Resistance and Protectant Fungicides
Chapter 11 Sanitation with Special Reference to Potato Blight
Summary
11.1. A Definition of Sanitation
11.2. How the Infection Rate Affects the Benefit from Sanitation
11.3. The Effect of the Sanitation Ratio
11.4. The Effect of Sanitation on Disease after the Logarithmic Phase
11.5. The Use of Eqs. (11.1) and (11.2) when Disease Is in Foci
11.6. Phytophthora infestans from Potato Cull Piles
11.7. Focal Outbreaks and General Epidemics of Potato Blight
11.8. The Change from Focal Outbreaks to General Epidemics
11.9. The Delay of the General Epidemic as a Result of Destroying Cull Piles
11.10. Cull Piles and Blight Forecasts
11.11. The Increase in Yield as a Result of Sanitation
Chapter 12 Sanitation with Special Reference to Wheat Stem Rust
Summary
12.1. Potato Blight and Wheat Stem Rust Contrasted and Compared
12.2. Stem Rust and Barberry Eradication
12.3. Focal Outbreaks and General Epidemics of Wheat Stem Rust
12.4. Barberry Eradication and Wheat Stem Rust in Northwestern Europe
12.5. The Relation between Sanitation and the Percentage of Stem Rust in Ripe Fields
12.6. The Reduction by Sanitation of Loss in Yield
12.7. The Relation between Loss of Yield and the Area under Stem Rust Progress Curve
12.8. The Infection…