Part one GENERAL ASPECTS 4
chapter one INTRODUCTION 4
Prologue：The Issues 4
Plants and Disease 4
The Concept of Disease in Plants 5
Types of Plant Diseases 7
History of Plant Pathology and Early Significant Plant Diseases 8
Introduction 8
Plant Diseases as the Wrath of Gods—Theophrastus 9
Mistletoe Recognized as the First Plant Pathogen 14
Plant Diseases as the Result of Spontaneous Generation 16
Biology and Plant Pathology in Early Renaissance 16
Potato Blight—Deadly Mix of Ignorance and Politics 19
The Expanding Role o f Fungi as Causes o f Plant Disease 21
The Discovery o f the Other Causes o f Infectious Diseases 23
Nematodes—Protozoan Myxomycetes—Bacteria—Viruses.Protozoa—Mollicutes—Viroids—Serious Plant Diseases of Unknown Etiology 23
Koch’s Postulates 26
Viruses，Viroids，and Prions 27
Losses Caused by Plant Diseases 29
Plant diseases reduce the quantity and quality of plant produce. 29
White，Downey，and Dry Vineyards—Bring on the Bordeaux！ 30
Plant diseases may limit the kinds o f plants and industries in an area. 32
Chestnuts，Elms，and Coconut Palm Trees—Where have they gone？ 32
Plant diseases may make plants poisonous to humans and animals 37
Ergot，Ergotism，and LSD：a Bad Combination 37
Mycotoxins and Mycotoxicoses 39
Plant diseases may cause financial losses. 41
The Insect—Pathogen Connection：Multifaceted and Important 42
Plant Pathology in the 20th Century 45
Early Developments 45
The Descriptive Phase 45
The Experimental Phase 46
The Etiological Phase 46
The Search for Control of Plant Diseases 46
The Main Areas o f Progress 47
Chemical Control of Plant Diseases 47
Appearance of Pathogen Races Resistant to Bactericides and Fungicides 48
Public Concern about Chemical Pesticides 48
Alternative Controls for Plant Diseases 49
Interest in the Mechanisms by Which Pathogens Cause Disease 50
The Concept of Genetic Inheritance of Resistance and Pathogenicity 52
Epidemiology of Plant Disease Comes of Age 53
Plant Pathology Today and Future Directions 54
Molecular Plant Pathology 54
Aspects of Applied Plant Pathology 56
Plant Biotechnology—The Promise and the Objections 56
Food Safety 58
Bioterrorism，Agroterrorism，Biological Warfare，etc.Who，What，Why 59
Worldwide Development of Plant Pathology as a Profession 60
International Centers for Agricultural Research 60
Trends in Teaching and Training 61
Plant Disease Clinics 62
The Practice and Practitioners of Plant Pathology 63
Certification of Professional Plant Pathologists 63
Plant Pathology as a Part of Plant Medicine； the Doctor of Plant Medicine Program 64
Plant Pathologists’ Contributin to Crops and Society 65
Some Historical and Present Examples o f Losses Caused by Plant Diseases 65
Plant Diseases and World Crop Production 65
Crop Losses to Diseases，Insects and Weeds 66
Pesticides and Plant Diseases 69
Basic Procedures in the Diagnosis of Plant Diseases 71
Pathogen or Environment 71
Infectious Diseases 72
Parasitic Higher Plants—Nematodes—Fungi and Bacteria：Fungi—Bacteria and Mollicutes 72
Viruses and Viroids—More than One Pathogen 73
Noninfectious Diseases 73
Identification o f a Preciously Unknown Disease：Koch’s Postulates 74
chapter two PARASITISM AND DISEASE DEVELOPMENT 77
Parasitism and Pathogenicity 77
Host Range of Pathogens 78
Development of Disease in Plants 79
Stages in the Development of Disease：The Disease Cycle 80
Inoculation 80
Inoculation，Types of Inoculum，Sources of Inoculum，Landing or Arrival of Inoculum 80
Prepenetration Phenomena 82
Attachment of Pathogen to Host，Spore Germination and Perception of the Host Surface，Appressorium Formation and Maturation，Recognition between Host and Pathogen，Germination of Spores and Seeds，Hatching of Nematode Eggs 82
Penetration 87
Direct Penetration through Intact Plant Surfaces，Penetration through Wounds，Penetration through Natural Openings 87
Infection 89
Infection，Invasion，Growth and Reproduction of the Pathogen （Colonization） 89
Dissemination o f the Pathogen 96
Dissemination by Air，Dissemination by Water，Dissemination by Insects，Mites，Nematodes，and Other Vectors，Dissemination by Pollen，Seed，Transplants，Budwood，and Nursery Stock，Dissemination by Humans 96
Overwintering and/or Oversummering o f Pathogens 100
Relationships between Disease Cycles and Epidemics 102
chapter three EFFECTS OF PATHOGENS ON PLANT PHYSIOLOGICAL FUNCTIONS 106
Effects of Pathogens on Photosynthesis 106
Effect of Pathogens on Translocation of Water and Nutrients in the Host Plant 106
Interference with Upward Translocation of Water and Inorganic Nutrients 106
Effect on Absorption of Water by Roots 108
Effect on Translocation o f Water through the Xylem 108
Effect on Transpiration 108
Interference with the Translocation of Organic Nutrients through the Phloem 113
Effect of Pathogens on Host Plant Respiration 115
Respiration of Diseased Plants 117
Effect of Pathogens on Permeability of Cell Membranes 118
Effects of Pathogens on Transcription and Translation 118
Effect on Transcription 119
Effect on Translation 119
Effect of Pathogens on Plant Growth 119
Effect of Pathogens on Plant Reproduction 121
chapter four GENETICS OF PLANT DISEASE 125
Introduction 125
Genes and Disease—Variability in Organisms—Mechanisms o f Variability 126
General Mechanisms：Mutation—Recombination—Gene and Genotype Flow among Plant Pathogens—Population Genetics，Genetic Drift，and Selection—Life Cycles—Reproduction—Mating Systems—Out-crossing—Pathogen Fitness 129
Specialized Mechanisms of Variability in Pathogens：Sexual-like Processes in Fungi Heterokaryosis—Parasexualism—Vegetative Incompatibility—Heteroploidy 131
Sexual-like Processes in Bacteria and Horizontal Gene Transfer 132
Genetic Recombination in Viruses 133
Loss of Pathogen Virulence in Culture 133
Stages o f Variation in Pathogens 134
Types o f Plant Resistance to Pathogens 134
True Resistance：Partial，Quantitative，Polygenic，or Horizontal Resistance—R-Gene Resistance，Monogenic，or Vertical Resistance 136
Disease Escape—Tolerance to Disease 137
Genetics of Virulence in Pathogens and of Resistance in Host Plants 139
The Nature o f Resistance to Disease—Pathogenicity Genes in Plant Pathogens 142
Genes Involved in Pathogenesis and Virulence by Pathogens 142
Pathogenicity Genes o f Fungi controlling：Production o f Infection Structures—Degradation of Cuticle and Cell Wall—Secondary Metabolites— Fungal Toxins—Pathogenicity Signaling Systems 144
Pathogenicity Genes in Plant Pathogenic Bacteria controlling：Adhesion to Plant Surfaces—Secretion Systems—Enzymes that Degrade Cell Walls—Bacterial Toxins as Pathogenicity Factors— Extracellular Polysaccharides as Pathogenicity Factors—Bacterial Regulatory Systems and Networks—Sensing Plant Signaling Components—Other Bacterial Pathogenicity Factors 146
Pathogenicity Genes in Plant Viruses：—Functions Associated with the Coat Protein—Viral Pathogenicity Genes 149
Nematode Pathogenicity Genes 150
Genetics o f Resistance through the Hypersensitive Response 151
Pathogen-Derived Elicitors of Defense Responses in Plants 151
Avirulence （avr） Genes：One of the Elicitors of Plant Defense Responses Characteristics of avr Gene-Coded Proteins：—Their Structure and Function Role of avr Genes in Pathogenicity and Virulence 154
hrp Genes and the Type Ⅲ Secretion System 155
Resistance （R） Genes of Plants：Examples of R Genes—How Do R Genes Confer Resistance？-Evolution o f R Genes—Other Plant Genes for Resistance to Disease 155
Signal Transduction between Pathogenicity Genes and Resistance Genes：—Signaling and Regulation o f Programmed Cell Death—Genes and Signaling in Systemic Acquired Resistance 160
Examples o f Molecular Genetics o f Selected Plant Diseases：—The Powdery Mildew Disease—Magnaporthe grisea，the Cause o f Rice Blast—Fusarium，the Soilborne Plant Pathogen—Ustilago maydis and Corn Smut 161
Breeding of Resistant Varieties 165
Natural Variability in Plants—Breeding and Variability in Plants—Breeding for Disease Resistance Sources of Genes for Resistance—Techniques Used in Classical Breeding for Resistance—Seed，Pedigree，and Recurrent Selection—Tissue Culture and Genetic Engineering Techniques 165
Genetic Transformation o f Plant Cells for Disease Resistance 169
Advantages and Problems in Breeding for Vertical or Horizontal Resistance 169
Vulnerability of Genetically Uniform Crops to Plant Disease Epidemics 170
chapter five HOW PATHOGENS ATTACK PLANTS 177
Mechanical Forces Exerted By Pathogens on Host Tissues 177
Chemical Weapons of Pathogens 179
Enzymes in Plant Disease 180
Enzymatic Degradation of Cell Wall Substances 180
Cuticular Wax—Cutin—Pectic Substances—Cellulose— Cross-Linking Glycans （Hemicelluloses）—Suberin— Lignin—Cell Wall Flavonoids—Cell Wall Structural Proteins 180
Enzymatic Degradation of Substances Contained in Plant Cells 189
Proteins—Starch—Lipids 189
Microbial Toxins in Plant Disease 190
Toxins That Affect a Wide Range of Host Plants 190
Tabtoxin—Phaseolotoxin—Tentoxin—Cercosporin— Other Non-Host-Specific Toxins 191
Host-Specific or Host-Selective Toxins 193
Victorin，HV Toxin—T-Toxin [Cochliobolus （Helminthosporium） heterostrophus RaceT-Toxin]—C-Toxin—Alternaria alternata Toxins—Other Host-Specific Toxins 194
Growth Regulators in Plant Disease 196
Detoxification o f Low-Molecular Weight Antimicrobial Molecules 201
Promotion o f Bacterial Virulence By avr Genes 202
Role o f Type Ⅲ Secretion in Bacterial Pathogenesis 202
Pathogenicity and Virulence Factors in Viruses and Viroids 202
chapter six HOW PLANTS DEFEND THEMSELVES AGAINST PATHOGENS 208
Whatever the Plant Defense or Resistance，It Is Controlled by Its Genes 208
Non-host Resistance—Partial，Polygenic，Quantitative，or Horizontal Resistance—Monogenic，R Gene，or Vertical Resistance 208
Preexisting Structural and Chemical Defenses 210
Preexisting Defense Structures 210
Preexisting Chemical Defenses 211
Inhibitors Released by the Plant in Its Environment—Inhibitors Present in Plant Cells before Infection 211
Defense through Lack of Essential Factors 212
Lack o f Recognition between Host and Pathogen：Lack of Host Receptors and Sensitive Sites for Toxins—Lack o f Essential Substances for the Pathogen 212
Induced Structural and Biochemical Defenses 213
Recognition of the Pathogen by the Host Plant 213
Transmission of the Alarm Signal to Host Defense Providers：Signal Transduction 214
Induced Structural Defenses：Cytoplasmic Defense Reaction—Cell Wall Defense Structures 214
Histological Defense Structures：Formation of Cork Layers—Abscission Layers—Tyloses—Deposition of Gums 215
Necrotic Structural Defense Reaction：Defense through the Hypersensitive Response 217
Induced Biochemical Defenses in：Non-Host Resistance—In Partial，Quantitative （Polygenic，General，or Horizontal）Resistance：Function of Gene Products in Quantitative Resistance—The Mechanisms of Quantitative Resistance—Effect of Temperature on Quantitative Resistance 217
Induced Biochemical Defenses in the Hypersensitive Response （R Gene）Resistance 221
The Hypersensitive Response：Genes Induced During Early Infection—Functional Analysis of Plant Defense Genes—Classes of R Gene Proteins—Recognition of Avr Proteins of Pathogens by the Host Plant—How Do R and Avr Gene Products Activate Plant Responses？—Some Examples of Plant Defense through R Genes and Their Matching Avr Genes：—The Rice Pi-ta Gene.The Tomato Cf Genes.The Tomato Bs2 Gene.The Arabidopsis RPM1 Gene—The Co-function of Two or More Genes. 221
Defense Involving Bacterial Type Ⅲ Effector Proteins 229
Production of Active Oxygen Species，Lipoxygenases，and Disruption of Cell Membranes—Reinforcement of Host Cell Walls with Strengthening Molecules 231
Production of Antimicrobial Substances in Attacked Host Cells—Pathogenesis-Related （PR）Proteins 232
Defense through Production of Secondary Metabolites—Phenolics：—Simple Phenolic Compounds—Toxic Phenolics from Nontoxic Phenolic Glycosides—Role of Phenol-Oxidizing Enzymes in Disease Resistance—Phytoalexins 233
Detoxification of Pathogen Toxins by Plants—Immunization of Plants against Pathogens：Defense through Plantibodies 236
Resistance through prior Exposure to Mutants of Reduced Pathogenicity 237
Systemic Acquired Resistance：—Induction by Artificial Inoculation with Microbes or by Treatment with Chemicals 237
Defense through Genetically Engineering Disease-Resistant Plants 242
With Plant-Derived Genes—With Pathogen-Derived Genes 242
Defense through RNA Silencing by Pathogen-Derived Genes 242
chapter seven ENVIRONMENTAL EFFECTS ON THE DEVELOPMENT OF INFECTIOUS PLANT DISEASE 251
Introduction 251
Effect of Temperature 253
Effect of Moisture 257
Effect of Wind 257
Effect of Light 257
Effect of Soil pH and Soil Structure 257
Effect of Host-Plant Nutrition 257
Effect of Herbicides 262
Effect of Air Pollutants 262
chapter eight PLANT DISEASE EPIDEMIOLOGY 266
The Elements of an Epidemic 266
Host Factors That Affect the Development of Epidemics 267
Levels of Genetic Resistance or Susceptibility of the Host—Degree of Genetic Uniformity of Host Plants—Type of Crop—Age of Host Plants 267
Pathogen Factors That Affect Development of Epidemics 269
Levels of Virulence—Quantity of Inoculum Near Hosts—Type of Reproduction of the Pathogen— Ecology of the Pathogen—Mode of Spread of the Pathogen 269
Environmental Factors That Affect Development of Epidemics 271
Moisture—Temperature 271
Effect of Human Cultural Practices and Control Measures 272
Site Selection and Preparation—Selection of Propagative Material—Cultural Practices—Disease Control Measures—Introduction of New Pathogens 272
Measurement of Plant Disease and of Yield Loss 273
Patterns of Epidemics—Comparison of Epidemics—Development of Epidemics—Modeling of Plant Disease Epidemics—Computer Simulation of Epidemics 274
Forecasting Plant Disease Epidemics 281
Evaluation of Epidemic Thresholds—Evaluation of Economic Damage Threshold—Assessment of Initial Inoculum and of Disease—Monitoring Weather Factors That Affect Disease Development 281
New Tools in Epidemiology 283
Molecular Tools.GIS.Remote Sensing.Image Analysis.Information Technology 283
Examples of Plant Disease Forecast Systems 285
Forecasts Based on Amount of Initial Inoculum—On Weather Conditions Favoring Development of Secondary Inoculum—On Amounts of Initial and Secondary Inoculum 285
Disease-Warning Systems—Development and Use of Expert Systems in Plant Pathology—Decision Support Systems 289
chapter nine CONTROL OF PLANT DISEASES 295
Control Methods that Exclude the Pathogen from the Host 295
Quarantines and Inspections—Crop Certification—Evasion or Avoidance of Pathogen—Use of Pathogen-Free Propagating Material—Pathogen-Free Seed—Pathogen-Free Vegetative Propagating Materials—Exclusion of Pathogens from Plant Surfaces by Epidermal Coatings 295
Control Methods that Eradicate or Reduce Pathogen Inoculum 298
Cultural Methods that Eradicate or Reduce the Inoculum：—Host Eradication—Crop Rotation—Sanitation—Creating Conditions Unfavorable to the Pathogen—Polyethylene Traps and Mulches 300
Biological Methods that Eradicate or Reduce the Inoculum：—Suppressive Soils 303
Reducing Amount of Pathogen Inoculum through Antagonistic Microorganisms Soilborne Pathogens—Aerial Pathogens—Mechanisms of Action—Control through Trap Plants—Control through Antagonistic Plants 305
Physical Methods that Eradicate or Reduce the Inoculum—Control by Heat Treatment—Soil Sterilization by Heat—Soil Solarization Hot-Water Treatment of Propagative Organs—Hot-Air Treatment of Storage Organs Control by Eliminating Certain Light Wavelengths—Drying Stored Grains and Fruit—Disease Control by Radiation—Trench Barriers against Root-transmitted Tree Diseases 310
Chemical Methods that Eradicate or Reduce the Inoculum—Soil Treatment with Chemicals—Fumigation—Disin festation of Warehouses—Control of Insect Vectors 312
Cross Protection—Induced Resistance：SystemicAcquired Resistance—Plant Defense Activators—Improving the Growing Conditions of Plants—Use of Resistant Varieties 314
Control through Use of Transgenic Plants Transformed for Disease Resistance Transgenic Plants that Tolerate Abiotic Stresses—Transgenic Plants Transformed with：Specific Plant Genes for Resistance—with Genes Coding for Anti-pathogen Compounds—with Nucleic Acids that Lead to Resistance and to Pathogen Gene Silencing—with Combinations of Resistance Genes—Producing Antibodies against the Pathogen—Transgenic Biocontrol Microorganisms 319
Direct Protection of Plants from Pathogens 322
By Biological Controls：—Fungal Antagonists：Heterobasidion （Fomes） annosum by Phleviopsis （Peniophora） gigantea—Chestnut Blight with Hypovirulent Strains of the Pathogen—Soilborne Diseases—Diseases of Aerial Plant Parts with Fungi&— Postharvest Diseases Bacterial Antagonists：Soilborne Diseases—Diseases of Aerial Plant Parts with Bacteria—Postharvest Diseases—with Bacteria of Bacteria-Mediated Frost Injury 328
Viral Parasites of Plant Pathogens 328
Biological Control of Weeds 328
Direct Protection by Chemicals 329
Methods of Application of Chemicals for Plant Disease Control—Foliage Sprays and Dusts—Seed Treatment—Soil Treatment—Treatment of Tree Wounds—Control of Postharvest Diseases 332
Types of Chemicals Used for Plant Disease Control 338
Inorganic—Inorganic Sulfur Compounds—Carbonate Compounds—Phosphate and Phosphonate Compounds— Film-Forming Compounds 338
Organic Chemicals：Contact Protective Fungicides—Organic Sulfur Compounds：Ditihiocarbamates 339
Systemic Fungicides：—Heterocyclic Compounds—Acylalanines—Benzimidazoles—Oxanthiins—Organophosphate Fungicides—Pyrimidines—Trizoles—Strobilurins or QoI Fungicides—Miscellaneous Systemics 340
Miscellaneous Organic Fungicides—Antibiotics—Petroleum Oils and Plant Oils—Electrolyed Oxidizing Water—Growth Regulators—Nematicides：—Hologenated Hydrocarbons—Organophosphate Nematicides—Isothiocoyanates—Carbamates—Miscellaneous Nematicides 343
Mechanisms of Action of Chemicals Used to Control Plant Diseases—Resistance of Pathogens to Chemicals—Restrictions on Chemical Control of Plant Diseases 345
Integrated Control of Plant Diseases：—In a Perennial Crop—In an Annual Crop 348
Part two SPECIFIC PLANT DISEASES 358
chapter ten ENVIRONMENTAL FACTORS THAT CAUSE PLANT DISEASES 358
Introduction：General Characteristics—Diagnosis—Control 358
Temperature Effects：High-Temperature Effects— Low-Temperature Effects—Low- Temperature Effects on Indoor Plants 358
Moisture Effects：Low Soil Moisture Effects—Low Relative Humidity—High Soil Moisture Effects 365
Inadequate Oxygen 367
Light 368
Air Pollution 368
Nutritional Deficiencies in Plants 372
Soil Minerals Toxic to Plants 372
Herbicide Injury 378
Other Improper Agricultural Practices 381
The Often Confused Etiology of Stress Diseases 383
chapter eleven PLANT DISEASES CAUSED BY FUNGI 383
Introduction 383
Some Interesting Facts about Fungi （Box） 387
Characteristics of plant pathogenic fungi 388
Morphology—Reproduction—Ecology—Dissemination 388
Classification of Plant Pathogenic Fungi 390
Fungallike Organisms—The True Fungi 391
Identification：Symptoms Caused by Fungi on Plants 397
Isolation of fungi （and Bacteria） 398
Preparing for Isolation—Isolating the Pathogen 398
Life Cycles of Fungi 402
Control of Fungal Diseases of Plants 403
Diseases Caused by Fungallike Organisms 404
Diseases Caused by Myxomycota （Myxomycetes） 404
Diseases Caused by Plasmodiophoromycetes 405
Clubroot of Crucifers 407
Diseases Caused by Oomycetes 409
Pythium Seed Rot，Damping-off，Root Rot，and Soft Rot 410
Phytophthora Diseases 414
Phytophthora Root and Stem Rots—Phytophthoras Declare War on Cultivated Plants and on Native Tree Species （Box） 414
Late Blight of Potatoes 421
The Downy Mildews 427
Introduction—Downy Mildew of Grape 428
Diseases Caused by True Fungi 433
Diseases Caused by Chytridiomycetes 433
Diseases Caused by Zygomycetes 434
Diseases Caused by Ascomycetes and Mitosporic Fungi 439
Sooty molds—Taphrina leaf Curl Diseases—Powdery Mildews 440
Foliar Diseases Caused by Ascomycetes and Deuteromycetes （Mitosporic Fungi） 452
Alternaria Diseases—Cladosporium Diseases—Needle Casts and Blights of Conifers 452
Mycosphaerella Diseases：Banana Leaf Spot or Sigatoka Disease 458
Septoria Diseases—Cercospora Diseases—Rice Blast Disease 460
Cochliobolus，Pyrenophora and Setosphaeria Diseases of Cereals and Grasses 466
Diseases of Corn：—Southern Corn Leaf Blight—Northern Corn Leaf Blight—Northern Corn Leaf Spot 466
Diseases of Rice—Brown Spot Disease of Rice 468
Cochliobolus Diseases of Wheat，Barley，and Other Grasses 469
Crown Rot and Common Root Rot—Spot Blotch of Barley and Wheat 469
Pyrenophora Diseases of Wheat，Barley and Oats 469
Net Blotch of Barley—Barley Stripe—Tan Spot of Wheat 469
Stem and Twig Cankers Caused by Ascomycetes and Deuteromycetes（Mitosporic Fungi） 473
Black Knot of Plum and Cherry—Chestnut Blight— Nectria Canker—Leucostoma Canker 476
Cankers of Forest Trees：—Hypoxylon Canker—Pitch Canker—Butternut Canker—Phomopsis Blight—Seiridium Canker 481
Anthracnose Diseases Caused by Ascomycetes and Deureromycetes （Mitosporic Fungi） 483
Black Spot of Rose 485
Elsinoe Anthracnose and Scab Diseases：—Grape Anthracnose or Bird’s-eye Rot—Raspberry Anthracnose—Citrus Scab Diseases—Avocado Scab 486
Colletotrichum Diseases：Colletotrichum Anthracnose Diseases of Annual Plants 487
Anthracnose of Beans—Anthracnose of Cucurbits—Anthracnose or Ripe Rot of Tomato—Onion Anthracnose or Smudge—Strawberry Anthracnose—Anthracnose of Cereals and Grasses 490
Colletotrichum Anthracnoses：A Menace To Tropical Crops （Box） Colletotrichum 491
Bitter Rot of Apple—Ripe Rot of Grape 494
Gnomonia Anthracnose and Leaf Spot Diseases 498
Dogwood Anthracnose 501
Fruit and General Diseases Caused by Ascomycetes and Deuteromycetes（Mitosporic Fungi） 501
Ergot of Cereals and Grasses—Apple Scab—Brown Rot of Stone Fruits—Monoliophthora Pod Rot of Cacao—Botrytis Diseases—Black Rot of Grape—Cucurbit Gummy Stem Blight and Black Rot—Diaporthe，Phomopsis，and Phoma Diseases—Stem Canker of Soybeans—Melanose Disease of Citrus—Phomopsis Diseases—Black Rot of Apple 501
Vascular Wilts Caused by Ascomycetes and Deuteromycetes （Mitosporic Fungi） 522
Fusarium Wilts：O f Tomato—Fusarium or Panama Wilt of Banana 523
Verticillium Wilts 526
Ophiostoma Wilt of Elm Trees：Dutch Elm Disease 528
Ceratocystis Wilts—Oak wilt—Ceratocystis Wilt of Eucalyptus 532
Root and Stem Rots Caused by Ascomycetes and Deuteromycetes （Mitosporic Fungi） 534
Gibberella Diseases—Gibberella Stalk and Ear Rot，and Seedling Blight of Corn 535
Fusarium （Gibberella） Head Blight （FHB） or Scab of Small Grains 535
Fusarium Root and Stem Rots of Non-Grain Crops 538
Take-All of Wheat—Thielavopsis Black Root Rot—Monosporascus Root Rot and Vine Decline of Melons 540
Sclerotinia Diseases：Sclerotinia Diseases of Vegetables and Flowers—Phymatotrichum Root Rot 546
Postharvest Diseases of Plant Products Caused by Ascomycetes and Deuteromycetes 553
Postharvest Decays of Fruits and Vegetables 556
Aspergillus，Penicillium，Rhizopus，and Mucor—Alternaria—Botrytis—Fusarium—Geotrichum—Penicillium—Sclerotinia 556
Control of Postharvest Decays of Fresh Fruits and Vegetables 557
Postharvest Decays of Grain and Legume Seeds 558
Mycotoxins and Mycotoxicoses 559
Aspergillus Toxins—Aflatoxins 559
Fusarium Toxins—Other Aspergillus Toxins and Penicillium Toxins 559
Control of Postharvest Grain Decays 560
Diseases Caused by Basidiomycetes 562
The Rusts—The Smuts—Root and Stem Rots—Wood Rots and Decays—Witches’Broom 562
The Rusts 562
Cereal Rusts—Stem Rust of Wheat and Other Cereals 565
Rusts of Legumes—Bean Rust—Soybean Rust—A Major Threat to a Major Crop （Box） 571
Cedar-Apple Rust—Coffee Rust 574
Rusts of Forest Trees：—White Pine Blister Rust—Fusi form Rust 577
The Smuts 582
Corn Smut—Loose Smut of Cereals—Covered Smut，or Bunt，of Wheat 588
Karnal Bunt of Small Grains-Legitimate Concerns and Political Predicaments （Box） 592
Root and Stem Rots Caused by Basidiomycetes 593
Root and Stem Rot Diseases Caused by the “Sterile Fungi” Rhizoctonia and Sclerotium 593
Rhizoctonia Diseases—Sclerotium Diseases 594
Root Rots of Trees 602
Armillaria Root Rot of Fruit and Forest Trees 602
Wood Rots and Decays Caused by Basidiomycetes 604
Witches’ Broom of Cacao 611
chapter twelve PLANT DISEASES CAUSED BY PROKARYOTES：BACTERIA AND MOLLICUTES 616
Introduction 616
Plant Diseases Caused by Bacteria 618
Characteristics of Plant Pathogenic Bacteria 618
Morphology—Reproduction—Ecology and Spread—Identification of Bacteria—Symptoms Caused by Bacteria—Control of Bacterial Diseases of Plants 618
Bacterial Spots and Blights 627
Introduction—Wildfire of Tobacco—Bacterial Blights of Bean—Angular Leaf Spot of Cucumber—Angular Leaf Spot or Bacterial Blight of Cotton—Bacterial Leaf Spots and Blights of Cereals and Grasses—Bacterial Spot of Tomato and Pepper—Bacterial Speck of Tomato—Bacterial Fruit Blotch o f Watermelon— Cassava Bacterial Blight—Bacterial Spot o f Stone Fruits 627
Bacterial Vascular Wilts 638
Bacterial Wilt o f Cucurbits—Fire Blight o f Pear and Apple—Southern Bacterial Wilt o f Solanaceous Plants—Bacterial Wilt or Moko Disease o f Banana—Ring Rot o f Potato 639
Bacterial Canker and Wilt o f Tomato—Bacterial Wilt （Black Rot） o f Cruci fers—Stewart’s Wilt o f Corn 651
Bacterial Soft Rots 656
Bacterial Soft Rots o f Vegetables 656
The Incalculable Postharvest Losses from Bacterial （and Fungal） Soft Rots （Box） 660
Bacterial Galls 662
Crown Gall 662
The Crown Gall Bacterium—The Natural Genetic Engineer （Box） 664
Bacterial Cankers 667
Bacterial Canker and Gummosis o f Stone Fruit Trees—Citrus Canker 667
Bacterial Scabs 674
Common Scab of Potato 667
Root Nodules of Legumes 675
Xylem-Inhabiting Fastidious Bacteria 678
Pierce’s Disease o f Grape—Citrus Variegated Chlorosis—Ratoon Stunting o f Sugarcane 679
Phloem-Inhabiting Fastidious Bacteria 683
Yellow Vine Disease o f Cucurbits—Citrus Greening Disease—Papaya Bunchy Top Disease 684
Plant Diseases Caused By Mollicutes：Phytoplasmas and Spiroplasmas 687
Properties o f True Mycoplasmas—Phytoplasmas—Spiroplasmas 688
Examples of Plant Diseases Caused by Mollicutes 691
Aster Yellows—Lethal Yellowing o f Coconut Palms—Apple Proliferation—European Stone Fruit Yellows—Ash Yellows—Elm Yellows （Phloem Necrosis）—Peach X-Disease—Pear Decline 691
Spiroplasma Diseases 699
Citrus Stubborn Disease—Corn Stunt Disease 691
chapter thirteen PLANT DISEASES CAUSED BY PARASITIC HIGHER PLANTS，INVASIVE CLIMBING PLANTS，AND PARASITIC GREEN ALGAE 705
Introduction—Parasitic Higher Plants 705
Dodder -Witchweed—Broomrapes—Dwarf Mistletoes o f Conifers—True or Leafy Mistletoes 706
Invasive Climbing Plants 716
Old World Climbing Fern—Kudzu Vine 717
Parasitic Green Algae：Cephaleuros 719
Plant Diseases Caused by Algae 719
chapter fourteen PLANT DISEASES CAUSED BY VIRUSES 724
Introduction 724
Characteristics of Plant Viruses 724
Detection—Morphology—Composition and Structure：O f Viral Protein—O f Viral Nucleic Acid 725
Satellite Viruses and Satellite RNAs 731
The Biological Function of Viral Components：Coding 731
Virus Infection and Virus Synthesis 731
Translocation and Distribution of Viruses in Plants 733
Symptoms Caused by Plant Viruses 734
Physiology of Virus-Infected Plants 737
Transmission of Plant Viruses By：Vegetative Propagation—Sap—Seed—Pollen—Insects—Mites—Nematodes—Fungi—Dodder 737
Epidemiology of Plant Viruses and Viroids 743
Purification of Plant Viruses—Serology of Plant Viruses 743
Nomenclature and Classification of Plant Viruses 747
Detection and Identification of Plant Viruses 751
Economic Importance of Plant Viruses 752
Control of Plant Viruses 753
Diseases Caused by Rigid Rod-Shaped Viruses 757
Diseases Caused by Tobamoviruses：—Tobacco Mosaic 757
The Contribution o f Tobacco Mosaic Virus to Biology and Medicine （Box） 757
Diseases Caused by Tobraviruses：—Tobacco Rattle by Furoviruses—by Hordeiviruses—by Pecluviruses—by Pomoviruses—by Benyviruses 758
Diseases Caused by Filamentous Viruses 762
Diseases Caused by Potexviruses—by Carlaviruses— by Capilloviruses and Trichoviruses—by Allexiviruses，Foveaviruses，and Vitiviruses 762
Diseases Caused by Potyviridae 764
Diseases Caused by Potyviruses 764
Bean Common Mosaic and Bean Yellow Mosaic—Lettuce Mosaic—Plum Pox—Papaya Ringspot—Potato Virus Y—Sugarcane Mosaic—Tobacco Etch—Turnip Mosaic—Watermelon Mosaic—Zucchini Yellow Mosaic 767
Diseases Caused by Ipomoviruses，Macluraviruses，Rymoviruses，and Tritimoviruses—by Bymoviruses 773
Diseases Caused by Closteroviridae 774
Diseases Caused by Closteroviruses：—Citrus Tristeza—Beet YellowsDiseases Caused by Criniviruses：—Lettuce Infectious Yellows 774
Diseases Caused by Isometric Single-Stranded RNA Viruses 779
Diseases Caused by Sequiviridae，Genus Waikavirus 779
Rice TungroDiseases Caused by Tombusviridae 779
Diseases Caused by Luteoviridae 781
Barley Yellow Dwarf—Potato Leafroll—Beet Western Yellows 781
Diseases Caused by Monopartite Isometric （＋）ssRNA Viruses of Genera Not Yet Assigned to Families 783
Diseases Caused by Comoviridae 784
Diseases Caused by Comoviruses 784
Diseases Caused by Nepoviruses 784
Tomato Ring Spot—Grapevine Fanleaf—Raspberry Ring Spot 785
Diseases Caused by Bromoviridae 787
Diseases Caused by Cucumoviruses 787
Cucumber Mosaic 788
Diseases Caused by Ilarviruses：Prunus Necrotic Ring Spot 790
Diseases Caused by Isometric Double-Stranded RNA Viruses 792
Diseases Caused by Reoviridae 792
Diseases Caused by Negative RNA [（-）ssRNA] Viruses 794
Plant Diseases Caused by Rhabdoviruses 794
Plant Diseases Caused by Tospoviruses 795
Plant Diseases Caused by Tenuiviruses 799
Diseases Caused by Double-Stranded DNA Viruses 801
Diseases Caused by Caulimoviruses and Other Isometric Caulimoviridae 801
Diseases Caused by Badnaviruses 803
Diseases Caused by Single-Stranded DNA Viruses 805
Plant Diseases Caused by Geminiviridae 805
Beet Curly Top—Maize Streak—African Cassava Mosaic—Bean Golden Mosaic—Squash Leaf Curl—Tomato Mottle—Tomato Yellow Leaf Curl 809
Plant Diseases Caused by Isometric Single-Stranded 813
DNA Viruses：The Circoviridae 813
Banana Bunchy Top 814
Coconut Foliar Decay 815
Viroids 816
Plant Diseases Caused by Viroids 816
Taxonomy （Grouping） of Viroids 816
Potato Spindle Tuber—Citrus Exocortis—Coconut Cadang-Cadang 820
chapter fifteen PLANT DISEASES CAUSED BY NEMATODES 826
Introduction 826
Characteristics of Plant Pathogenic Nematodes 827
Morphology—Anatomy—Life Cycles—Ecology and Spread—Classification 827
Isolation of Nematodes 831
Isolation o f Nematodes from Soil 831
Isolation o f Nematodes from Plant Material 832
Symptoms Caused by Nematodes 832
How Nematodes Affect Plants 833
Interrelationships between Nematodes and Other Plant Pathogens 835
Control of Nematodes 836
Important Nematodes and Diseases 838
Root-Knot Nematodes：Meloidogyne 838
Cyst Nematodes：Heterodera and Globodera 842
Soybean Cyst Nematode：Heterodera glycines 843
Sugar Beet Nematode：Heterodera schachtii 846
Potato Cyst Nematode：Globodera rostochiensis and Globodera pallida 847
The Citrus Nematode：Tylenchulus Semipenetrans 848
Lesion Nematodes：Pratylenchus 849
The Burrowing Nematode：Radopholus 853
The Added Significance o f Plant Nematodes in the Tropics and Subtropics （Box） 858
Stem and Bulb Nematode：Ditylenchus 858
Sting Nematode：Belonolaimus 860
Stubby-Root Nematodes：Paratrichodorus and Trichodorus 863
Seed-Gall Nematodes：Anguina 865
Foliar Nematodes：Aphelenchoides 867
Pine Wilt and Palm Red Ring Diseases：Bursaphelenchus 870
Pine Wilt Nematode：Bursaphelenchus xylophilus 870
Red Ring Nematode：Bursaphelenchus cocophilus 872
chapter sixteen PLANT DISEASES CAUSED BY FLAGELLATE PROTOZOA 875
Introduction 875
Nomenclature o f Plant Trypanosomatids—Taxonomy—Pathogenicity—Epidemiology and Control o f Plant Trypanosomatids 877
Plant Diseases Caused by： 878
Phloem-Restricted Trypanosomatids 878
Phloem Necrosis of Coffee—Hartrot of Coconut Palms—Sudden Wilt （Marchitez Sopresiva） of Oil Palm—Wilt and Decay of Red Ginger 878
Latici fer-Restricted trypanosomatids 882
Empty Root of Cassava 882
Fruit-and Seed-Infecting Trypanosomatids 882
Fruit Trypanosomatids 882
Glossary 887
Index 903