The Nature of Wilt Diseases of Plants

The Nature of Wilt Diseases of Plants

The ultimate objective of this book is to advance the ongoing process of modeling vascular diseases of plants, especially Fusarium wilt of tomato. The book features a review of what is known about wilt diseases and then develops a framework in which past, present, and future findings can be classified and correlated.

Contents

Preface; Introduction; The Production, Persistence, and Presentation of Inoculum; Growth and Reproduction in Moribund Tissues of the Host; The Persistence of Fusarium in the Soil; The Colonization of Root Surfaces; Suscept-Parasite Contacts--The Transition Between Persistence in the Soil and Extended Parasitic Growth; Disease Expression in Conducive Versus Suppressive Soils; Fusarium Crown and Root Rot--A Special Case; Modeling the Survival of Fusarium and Its Initial Contact with the Host; Defense Strategies of the Plant; Innate Structural Barriers; Recognition Phenomena; General Defense Responses; Determinative Phase I: Success or Failure of the Pathogen in Penetrating to the Vascular System of the Host; Determining Phase II: Success or Failure of the Pathogen in Colonizing the Vascular System; Modeling the Interaction Between Host and Parasite Within the Vascular System; Defining Parameters of the Model; Defining Components Within the Model; Defenses in the Lateral Direction; Defense in a Longitudinal Direction; A Perspective on Vascular Occlusion; The Activation of the Hormonal System of the Host; Vascular Gels and Gums and Vessel Coatings; Tyloses, Isodiametric Growth, and Increased Vascularization; The Synthesis of Stress Metabolites by the Host in Response to Infection; The Accumulation of Phenolics Following Infection and Their Relation to the Resistance Process; The Lignification and Suberization of Infected Tissues; Phytoalexins Produced in Response to Stress; Other Host Responses That Contribute to Defense; The Defense Strategies of the Plant; Colonization of the Vascular System by the Pathogen; Defining Pathogen Factors That Disrupt Host Defenses; Avoiding or Overcoming Recognition; Avoiding or Overcoming Callose Deposition; Avoiding or Overcoming Vascular Gelation; Avoiding or Overcoming Vascular Blockage by Tylose Occlusion or Vessel Crushing; Avoiding or Overcoming Stress Metabolites; The Suppression of Responses as Reflected in Respiration; Some Thoughts on the Suppressions of Responses; The Expressive Phase of the Disease; The Causes of Wilting--The Great Debate; The Evidence for Vascular Plugging and the Failure of the Water Supply; The Toxin Hypothesis in Relation to Symptom Expression; A Role for Toxins Produced by the Pathogen?; Genetic Variation in the Host and Pathogen; Resistance of Tomato to Fusarium oxysporum f. sp. lycopersici Race 1; Resistance of Tomato to Fusarium oxysporum f. sp. lycopersici Races 2 and 3 and to F.o. f.sp. radicis-lycopersici; Resistance of Tomato to Related Disease Organisms; Genetic Variation and Taxonomy of the Pathogens; Genetic Studies of Fusarium oxysporum; Classification and Nomenclature of Host and Pathogen in Terms of Their Interactions; The Cataloging and Mapping of Genes; Environmental Factors in Disease Development; Temperature; Light; Soil Moisture and Aeration; The Effect of Nutrients on Wilt Development; Calcium Nutrition and Soil pH; Nitrogen Nutrition; The Effect of Nonpathogenic Microflora on Disease Development; The Effect of Nematode Infections on Wilt Expression; Control Measures; Reducing Inoculum Load in the Soil; The Problem of Soil Reinfestation; The Control of Soil Reinfestation; The Use of Systemic Chemicals for Wilt Control; The Limitations of Chemical Control; The Use of Biological Control; The Selection, Development, and Maintenance of Suppressive Soils; Altering the Soil Nutrients; The Use of Resistant Cultivars; Building a Strategy for Control; A Look Toward the Future; References