"This book aims to provide readers with the latest information on important virus diseases of crops in tropical and subtropical countries and the envisaged directions into the future of plant virus control. The volume comprises 18 chapters. The first chapter covers general information on the impact of virus diseases, methods for estimating disease severity, recent data on host-virus interactions, serological and molecular techniques for the diagnosis of virus pathogens, and disease management strategies. Subsequent chapters examine selected virus diseases, inclusive of the hosts, vectors and viruses and their intricate relationships, symptoms development, virus transmission, host resistance and the underlying biochemical and genetic factors leading to disease, as well as their control using a variety of techniques including genetic modification. The structure of the various virus epidemics covered in this book is different and complex, dependent on the nature of the virus or viruses, their relationship with their vectors, geographical location, among other factors such as political and social approaches that deal with food security. Much progress has been achieved, but there is much work remaining on the pursuit and development of knowledge-based disease management strategies, regulatory policies and synergies between all the stakeholders.".

• Virus Diseases of Tropical and Subtropical Crops
• Copyright
• Contents
• Contributors
• Preface
• 1: Viruses Affecting Tropical and Subtropical Crops: Biology, Diversity, Management
  • 1.1 Introduction
  • 1.2 Biology: Structure, Taxonomy and Diversity
    • 1.2.1 Virus evolution and the emergence of new diseases
    • 1.2.2 Wild or non-crop plants as reservoirs and targets of ‘new’ causal agents of disease
    • 1.2.3 Virus–virus interactions
    • 1.2.4 Plant–virus interactions
  • 1.3 Plant Virus–Vector Interactions
  • 1.4 Diagnosis and Crop Protection Technologies
  • 1.5 Virus Diseases Threaten Food Security in Tropical and Subtropical Regions
  • References
• 2: Banana Bunchy Top
  • 2.1 Introduction
  • 2.2 Importance of Banana as the Main Host Plant of Banana Bunchy Top Disease
  • 2.3 Current Distribution of Banana Bunchy Top Disease
  • 2.4 Description of Banana bunchy top virus
  • 2.5 Transmission of Banana bunchy top virus in Banana Fields
    • 2.5.1 Disease spread
    • 2.5.2 P. nigronervosa: forms and distribution
    • 2.5.3 P. nigronervosa on Musa spp.
    • 2.5.3 Aphid distribution and location
    • 2.5.4 The disease incubation period
    • 2.5.5 Incidence of BBTD
  • 2.6 Banana Bunchy Top Disease Symptoms
  • 2.7 Diagnosis of Banana bunchy top virus
  • 2.8 Banana Bunchy Top Disease Control Options
  • 2.9 Concluding Remarks
  • Acknowledgements
  • References
• 3: Wheat Dwarf
  • 3.1 Introduction
  • 3.2 The Disease
  • 3.3 Main Characteristics of the Causal Agent of Wheat Dwarf Disease: The Wheat dwarf virus (es)
  • 3.4 Host Range of Wheat dwarf virus Isolates
  • 3.5 Transmission of the Virus
  • 3.5.1 Psammotettix vectors
  • 3.6 Diagnostic Methods for Wheat Dwarf Disease
  • 3.7 Management Strategies
  • 3.8 Concluding Remarks
  • Acknowledgments
  • References
• 4: Cassava Brown Streak
  • 4.1 Introduction: Disease and Symptoms
    • 4.1.1 First reports and disease aetiology
    • 4.1.2 Symptoms
  • 4.2 Distribution
    • 4.2.1 Early years (1930s–2004)
    • 4.2.2 New epidemics (2004 to the present)
  • 4.3 Economic Impact
    • 4.3.1 Plant and crop-level estimates of economic impact
    • 4.3.2 Global-level estimates of economic impact
  • 4.4 Viral Aetiology
  • 4.5 Virus Taxonomy, Genome Organization and Diversity
  • 4.6 Host Range
    • 4.6.1 Natural hosts
    • 4.6.2 Experimental hosts
  • 4.7 Transmission and Epidemiology
    • 4.7.1 Virus propagation and vector transmission
    • 4.7.2 Epidemiology
  • 4.8 Diagnostic Methods
  • 4.9 Management Strategies
    • 4.9.1 Phytosanitation
    • 4.9.2 Use of resistant varieties
      • Conventional approaches to enhancing host plant resistance
      • Molecular approaches to enhancing the selection of host plant resistance
    • 4.9.3 Vector control
  • 4.10 Concluding Remarks
  • References
• 5: Cassava Mosaic
  • 5.1 General Introduction
  • 5.2 Symptoms
  • 5.3 Causative Viruses
  • 5.4 Genome Structure, Function and Diversity
  • 5.5 Host Range
  • 5.6 Transmission and Epidemiology
  • 5.7 Diagnostics
  • 5.8 Distribution
  • 5.9 Economic Impact
  • 5.10 Management
    • 5.10.1 Natural and transgenic resistance to cassava mosaic disease
    • 5.10.2 Cassava mosaic disease avoidance and cultural control
    • 5.10.3 Whitefly management
    • 5.10.4 Cassava mosaic disease monitoring and forecasting
  • 5.11 Concluding Remarks
  • References
• 6: Cucumber Mosaic
  • 6.1 Introduction
  • 6.2 Virion and genome properties
    • 6.2.1 Virions
    • 6.2.2 Genome
  • 6.3 Taxonomy
  • 6.4 Diversity
  • 6.5 Symptomatology
    • 6.5.1 Cucurbits
    • 6.5.2 Pepper
    • 6.5.3 Tomato
    • 6.5.4 Bean
    • 6.5.5 Chickpea and Cowpea
    • 6.5.6 Banana
    • 6.5.7 Co-infections
  • 6.6 Host Range
  • 6.7 Transmission
  • 6.8 Detection and Diagnosis
  • 6.9 Ecology and Epidemiology
  • 6.10 Control
    • 6.10.1 Transgenic approaches
    • 6.10.2 Crop-specific control measures
      • Cucurbits
      • Spinach and lettuce
      • Pepper
      • Tomato
      • Banana
      • Forage legumes
      • Ornamentals
  • 6.11 Concluding Remarks
  • Acknowledgements
  • References
• 7: Potato Mosaic and Tuber Necrosis
  • 7.1 Introduction: The Aetiologic Agent, Disease Symptoms, Distribution and Economic Importance
  • 7.2 Host Range and Transmission
  • 7.3 Classification of Potato virus Y Strains
  • 7.4 Geographic Distribution of Potato virus Y Strains and Population Structure
  • 7.5 Diagnostic Methods and Management Strategies
  • 7.6 Concluding Remarks
  • Acknowledgments
  • References
• 8: Soybean Mosaic
  • 8.1 Introduction
  • 8.2 Soybean mosaic virus Effects in Soybean
  • 8.3 Transmission
  • 8.4 Host Range
  • 8.5 Taxonomy and Genome Organization
  • 8.6 Soybean mosaic virus Diversity
  • 8.7 Diagnostic Methods
  • 8.8 Management Strategies
  • 8.9 Concluding Remarks
  • References
• 9: Yam Mosaic
  • 9.1 Introduction
  • 9.2 Disease and Symptoms
  • 9.3 Distribution
  • 9.4 Economic Impact
  • 9.5 Causative Virus
  • 9.6 Host Range
  • 9.7 Transmission
  • 9.8 Diagnostic Methods
  • 9.9 Management Strategies
  • 9.10 Future Perspectives
  • References
• 10: Sugarcane Mosaic
  • 10.1 Structure, Taxonomy and Diversity
  • 10.2 Genetics, Strains and Phylogenetics
  • 10.3 Disease Symptoms, Host Range and Transmission
  • 10.4 Distribution
  • 10.5 Economic Impact
  • 10.6 Host Resistance and Plant–Virus Interactions
  • 10.7 Diagnosis and Management
  • 10.8 Management Strategies
  • 10.9 Concluding Remarks
  • References
• 11: Papaya Ringspot
  • 11.1 Introduction: Disease and Symptoms
  • 11.2 Distribution
  • 11.3 Economic Impact
  • 11.4 Causative Virus
  • 11.5 Taxonomy, Strains and Phylogenetics
  • 11.6 Transmitting Vector
  • 11.7 Diagnostic Methods and Management Strategies
  • 11.8 Concluding Remarks
  • References
• 12: Tomato Spotted Wilt
  • 12.1 Introduction
  • 12.2 Characterization of Tospoviruses
    • 12.2.1 Morphology and genome organization
    • 12.2.2 Taxonomy
    • 12.2.3 Serological grouping
  • 12.3 Economic Importance of the Disease and Transmission of the Virus
    • 12.3.1 Agricultural impact of tospoviruses
    • 12.3.2 Persistent transmission by thrips
  • 12.4 Diagnosis and Detection of Tospoviruses
  • 12.4.1 Serological assays
  • 12.4.2 Nucleic acid amplification
  • 12.4.3 Deep sequencing analysis
  • 12.5 Management of Tospoviral Diseases
  • 12.6 Concluding Remarks
  • References
• 13: Tomato Yellow Leaf Curl
  • 13.1 Introduction
  • 13.2 Characteristic Symptoms
  • 13.3 Economic Impact
  • 13.4 Geographic Distribution
  • 13.5 Genome Organization
  • 13.6 Main Ecotypes
  • 13.7 Transmission
  • 13.8 Control Strategies
  • 13.9 Concluding Remarks
  • References
• 14: Tristeza
  • 14.1 Introduction
  • 14.2 Disease
    • 14.2.1 Host range
    • 14.2.2 Symptomatology
    • 14.2.3 Transmission
  • 14.3 Molecular Biology
    • 14.3.1 Replication and gene function
    • 14.3.2 Plant–pathogen interactions
    • 14.3.3 Phylogeny of strains
  • 14.4 Diagnostics
  • 14.5 Management Strategies
    • 14.5.1 Control strategies
    • 14.5.2 Resistance
  • 14.6 From Foe to Friend: Citrus tristeza virus Vectors
  • 14.7 Concluding Remarks
  • References
• 15: Rice Tungro
  • 15.1 Introduction
  • 15.2 Disease Symptoms
  • 15.3 Distribution
  • 15.4 Economic Impact
  • 15.5 Causative Viruses
  • 15.6 Taxonomy
  • 15.7 Host Range
  • 15.8 Transmission
  • 15.9 Molecular Biology
    • 15.9.1 General features
    • 15.9.2 Gene functions
    • 15.9.3 Promoter activity
    • 15.9.4 Variability
  • 15.10 Diagnostic Methods
  • 15.11 Management Strategies
    • 15.11.1 Conventional methods
    • 15.11.2 Non-conventional or transgenic methods
  • 15.12 Concluding Remarks
  • Acknowledgements
  • References
• 16: Sweet Potato Virus Disease
  • 16.1 Introduction
  • 16.2 Causative Viruses
    • 16.2.1 Sweet potato feathery mottle virus
    • 16.2.2 Sweet potato chlorotic stunt virus
  • 16.3 Diagnostic Methods
    • 16.3.1 Biological indexing
    • 16.3.2 Serological tests
    • 16.3.3 Electron microscopy
    • 16.3.4 Molecular techniques
  • 16.4 Management Strategies
    • 16.4.1 Cultural methods
    • 16.4.2 Distribution of virus-indexed material
    • 16.4.3 Resistance
      • Natural resistance
      • Engineered resistance
  • 16.5 Concluding Remarks
  • References
• 17: Mealybug Wilt Disease
  • 17.1 Introduction
  • 17.2 Disease Symptoms
  • 17.3 History of Research into the Aetiology of Mealybug Wilt Disease
  • 17.4 Ampeloviruses Infecting Pineapple
  • 17.5 Badnaviruses and Retroelements in Pineapple
  • 17.6 Mealybugs and Ants
  • 17.7 Summary of the Aetiology of MealybugWilt Disease
  • 17.8 Disease Management
  • 17.9 Concluding Remarks
  • References
• 18: Viruses affecting tropical and subtropical crops: future perspectives
  • References
• Index