Plant PathologyPDF电子书下载

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