Soil has a versatile role in supporting the development of a wide range of organisms, including plants and microorganisms. Soilborne pathogens and root diseases are the primary limiting factor in many crops and tend to be very difficult to control. This first volume of a two-volume set introduces disease-causing microorganisms including oomycetes, fungi, bacteria, and viruses found in soils. It focuses on the biology, detection, and identification of soilborne bacterial, fungal, and viral plant pathogens. Volume two provides information on ecology and epidemiology of soilborne microbial plant pathogens and strategies applicable to manage diseases. Chapters cover exclusion and prevention strategies; improvement of host plant resistance; biological management; application of chemicals; and integration of disease management strategies.

Soilborne microbial plant pathogens including oomycetes, fungi, bacteria and viruses cause several economically important destructive diseases and the symptoms of infection can be recognized only after the pathogen has invaded many tissues primarily vascular tissues of susceptible plants. This condition places formidable challenges in investigating different aspects of host-microbial pathogen interactions. Early detection of infection and precise identification, differentiation, and quantification of the microbial plant pathogens in plants, soil and water sources are essential requirements for development of effective tactics to reduce the incidence and spread of the diseases caused by them. As the microbial plant pathogens differ in their virulence and sensitivity to the environment and chemicals applied, it is imperative to assess the extent of variability in the concerned pathogens. This first volume of a two-volume set introduces disease-causing microorganisms including oomycetes, fungi, bacteria, and viruses found in soils. It focuses on the biology, detection, and identification of soilborne bacterial, fungal, and viral plant pathogens. This volume discusses various techniques based on biological, immunological and genetic properties of the pathogens indicating their advantages and limitations for selecting the appropriate technique to fulfill the requirements. Features: Presents techniques useful for detection, identification, quantification of microbial plant pathogens in plants, soil, and irrigation water from waterbodies. Highlights subversive activities of viruses, resulting in the breakdown of host defense systems. Discusses RNA silencing in infected plants by viruses and posttranscriptional gene silencing (PTGS) functioning as an endogenous mechanism in plants against virus infection. Presents information on methods of assessment of genetic variability and sensitivity of microbial plant pathogens to chemicals and adverse environmental conditions.

This book provides a timely review of concepts in plant disease management involving microbial soil suppressiveness and organic amendments. Topics discussed include the impact of suppressive soils on plant pathogens and agricultural productivity, the enhancement of soil suppressiveness through the application of compost and the development of disease suppressive soils through agronomic management. Further chapters describe diseases caused by phytopathogens, such as Pythium, Fusarium and Rhizoctonia, interaction of rhizobia with soil suppressiveness factors, biocontrol of plant parasitic nematodes by fungi and soil suppressive microorganisms.

Morphological, biological, biochemical and physiological characteristics have been used for the detection, identification and differentiation of fungal pathogens up to species level. Tests based on biological characteristics are less consistent. Immunoassays have been shown to be effective in detecting fungal pathogens present in plants and environmental samples. Development of monoclonal antibody technology has greatly enhanced the sensitivity and specificity of detection, identification and differentiation of fungal species and varieties/strains. Nucleic acid-based techniques involving hybridization with or amplification of unique DNA have provided results rapidly and reliably. Presentation of a large number of protocols is a unique feature of this volume.

Plant disease management remains an important component of plant pathology and is more complex today than ever before including new innovation in diagnostic kits, the discovery of new modes of action of chemicals with low environmental impact, biological control agents with reliable and persistent activity, as well as the development of new plant varieties with durable disease resistance. This book is a collection of invited lectures given at the 9th International Congress of Plant Pathology (ICPP 2008), held in Torino, August 24-29, 2008 and is part of a series of volumes on Plant Pathology in the 21st Century. It focuses on new developments of disease management and provides an updated overview of the state of the art given by world experts in the different fields of disease management. The different chapters deal with basic aspects of disease management, mechanisms of action of biological control agents, innovation in fungicide application, exploitation of natural compounds and resistance strategies. Moreover, the management of soil-borne diseases and disease management in organic farming are covered.

Healthy seeds and propagules are the basic requirement for producing good grains, fruits and vegetables needed for human survival and perpetuation. Dispersal of microbial plant pathogens via seeds and propagules has assumed more importance than other modes of dispersal, as infected seeds and propagules have the potential to become the primary sources of carrying pathogen inoculum for subsequent crops. Several diseases transmitted through seeds and propagules have been shown to have the potential to damage economies as a result of huge quantitative and qualitative losses in numerous crops. Hence, it is essential to rapidly detect, identify and differentiate the microbial plant pathogens present in seeds and propagules precisely and reliably, using sensitive techniques. Microbial Plant Pathogens: Detection and Management in Seeds and Propagules provides a comprehensive resource on seed-borne and propagule-borne pathogens. Information on the biology of microbial pathogens, including genetic diversity, infection process and survival mechanisms of pathogens and epidemiology of diseases caused by them, are discussed critically and in detail to highlight weak links in the life cycles of the pathogens. Development of effective disease management systems, based on the principles of exclusion and eradication of pathogens and immunization of crop plants to enhance the levels of resistance of cultivars to diseases, has been effective to keep the pathogens at bay. The need for production of disease-free seeds/propagules has been emphasized to prevent the carryover of the inoculum to the next crop or introduction of the pathogens to other locations. Effectiveness of adopting simple cultural practices and development of cultivars resistant to diseases through traditional breeding methods or biotechnological approach have resulted in reducing the pathogen inoculum and disease incidence. Although application of different chemicals may reduce the disease incidence effectively, biological management of crop diseases, employing potential biological control agents have to be preferred to preserve the agroecosystems. Greater efforts have to be made to integrate compatible strategies to enhance the effectiveness of diseases management systems. Protocols appended at the end of relevant chapters form a unique feature of this book to enable the researchers to fine-tune their projects. This 2 volume set provides comprehensive and updated information about the economically-important groups of microbial plant pathogens carried by seed and propagules. Graduate students, researchers and teachers of plant pathology, plant protection, microbiology, plant breeding and genetics, agriculture and horticulture, as well as certification and quarantine personnel will find the information presented in this book useful.

Crop disease management strategies revolve around the principles of exclusion, eradication and immunization. Cultural practices are aimed at preventing or reducing the accumulation of pathogen population (inoculum). Development of cultivars with genetic resistance by transgressing resistance gene(s) through traditional breeding procedures or biotechnological techniques is the most effective and acceptable strategy, as it is environment-friendly and does not need any additional cost to the grower. Assessment of different grades of resistance of cultivars or genotypes to soilborne microbial pathogens has been possible by quantifying pathogen populations or their DNA contents in the test plants by applying biological and molecular methods. This second volume of a two-volume set focuses on the soilborne microbial plant pathogens and the diseases caused by them. The book provides information on ecology and epidemiology of soilborne microbial plant pathogens and various strategies applicable for effective management of diseases. Chapters cover exclusion and prevention strategies; improvement of host plant resistance; biological management; application of chemicals; and integration of these disease management strategies. Features Discusses various aspects of soilborne microbial plant pathogens to develop effective methods of managing diseases. Presents information on epidemiology and ecology of soilborne microbial plant pathogens. Facilitates the application of management strategies alone or in combination with others for effective suppression of disease development. Features information on application of biotic and abiotic biological control agents (BCAs) to suppress pathogen development either by directly acting on the pathogen(s) or indirectly by enhancing host resistance to the pathogens. Employs biotic and abiotic biocontrol agents either to replace or reduce the use of chemicals is an achievable approach for managing the soilborne microbial pathogens.

As agricultural production increases to meet the demands of a growing world population, so has the pace of biotechnology research to combat plant disease. Diseases can be caused by a variety of complex plant pathogens including fungi, bacteria, viruses and nematodes, and their management requires the use of techniques in transgenic technology, biochemistry and genetics. While texts exist on specific pathogens or management practices, a comprehensive review is needed of recent developments in modern techniques and the understanding of how pathogens cause disease. This collection of studies discusses the key approaches to managing each group of pathogens within the context of recent developments in biotechnology. Broad themes include microbe-plant interactions, molecular diagnostics of plant pathogens and enhancing the resistance of plants.

The papers contained in this book were presented at a NATO Advanced Research Workshop (ARW) held at Cape Sounion, Athens, Greece, 19-24 May, 1991. The twenty-eight more comprehensive papers represent the key subjects of the ARW covered by invited speakers. The thirty-four short papers pre sented in a research format are contributions of those invited to participate in the ARW. There was a total of 70 participants from 21 countries. The objectives of the ARW were as follows: to review current knowledge of biological control of plant diseases and plant parasitic nematodes, with emphasis on mechanisms at the molecular, cellular, organismal, and ecosystem level; to examine and expand on current concepts and synthesize new concepts; to identify and prioritize limitations in the use of biological control for plant diseases and nematodes and the scientific research needed to overcome these limitations; and to develop strategies for biological control through management of resident agents or introduction of natural or modified agents.