Abstract This chapter defines food security as the condition reached when a nation's population has access to sufficient, safe, and nutritious food to meet its dietary needs and food preferences. It stresses China's importance to global food security because of its population size. The chapter introduces the contents of the volume and then treats briefly food security in ancient and dynastic (211 bc-1912) China. It examines environmental stressors, such as population growth, natural disasters, and insect pests as well as imperial responses (for example, irrigation, flood control, storage and transportation systems). The chapter also briefly int- duces the Republican era (1912-1949) and compares environmental stressors and government responses then to those of the imperial period. Keywords Food system * Food security * Food production regions * Environmental stressors (Population growth * Natural disasters * Insect pests and Plant diseases * Deforestation * Climate change) * Irrigation systems * Flood control * Grand Canal 1. 1 The Problem of Food Security and Environmental Change Food is the material basis to human survival, and in each nation-state, providing a system for the development, production, and distribution of food and its security is a primary national objective. Many forces have influenced the food security of peoples since ancient times, with particular challenges from natural disasters (floods, famines, drought, and pestilence) and growing populations globally.

Plants live in a constantly changing environment from which they cannot physically escape. Plants therefore need signalling and response mechanisms to adapt to new local conditions. The ef?cacy of such mechanisms underlies the plant performance during stress and therefore also impacts greatly on agricultural productivity. M- ulation of ion channel activity not only provides a means for rapid signal generation 2+ but also allows adjustment of cellular physiology. For example, Ca permeable ion 2+ channels can transduce environmental stimuli into Ca -encoded messages which can modify the gene expression. Furthermore, ion channel activity is essential to control cellular ion homeostasis that impacts on plant responses to drought, salinity, pathogens, nutrient de?ciency, heavy metals, xenobiotics and other stresses. This volume focuses on the crucial roles of different types of ion channel in plant stress responses. Functions of ion channels are discussed in the context of mechanisms to relay external and endogenous signals during stress and as mechanisms to regulate cellular ion homeostasis and enzymatic activities in the context of biotic and abiotic stress. The chapters presented cover cation and anion channels located in various cellular compartments and tissues.

As a collection of papers that includes material presented at the 2008 International Congress for Plant Pathology, this text features research right at the leading edge of the field. The latest findings are particularly crucial in their implications for fruit production; an important market sector where in some areas up to 50 per cent of the crop can be lost after harvest. While post-harvest fruit treatments with fungicides are the most effective means to reduce decay, rising concerns about toxicity have led to the development of alternative approaches to disease control, including biological methods, the subject of three chapters of this book. With several new techniques requiring modification of current post-harvest practices, it is more important than ever to stay abreast of the latest information. Other chapters deal with the mechanisms of host fruit and vegetable resistance, fungal pathogenicity factors and their relationship with the host response, and a number of subjects related to disease assessments before harvest as well as their relationship to the postharvest treatment of fruits and vegetables. The book also includes several useful case studies of crops such as kiwifruit and peaches, where different approaches at the pre- and post-harvest levels are combined to good effect. With food production issues gaining an ever higher profile internationally, this text makes an important contribution to the debate.

This collection of papers represents some of those given at the International Congress for Plant Pathology held in Turin in 2008 in the session with the title "The Role of Plant Pathology in Food Safety and Food Security". Although food safety in terms of "Is this food safe to eat?" did not receive much direct attention it is, never theless, an important topic. A crop may not be safe to eat because of its inh- ent qualities. Cassava, for example, is cyanogenic, and must be carefully prepared if toxicosis is to be avoided. Other crops may be safe to eat providing they are not infected or infested by microorganisms. Mycotoxins are notorious examples of compounds which may contaminate a crop either pre- or post-harvest owing to the growth of fungi. Two papers in this book deal with toxins, one by Barbara Howlett and co-workers and the other by Robert Proctor and co-workers. In the first of these, the role of sirodesmin PL, a compound produced by Leptosphaeria ma- lans, causal agent of blackleg disease of oilseed rape (Brassica napus), is discussed. The authors conclude that the toxin plays a role in virulence of the fungus and may also be beneficial in protecting the pathogen from other competing micro-organisms but there seem to be no reports of its mammalian toxicity.

The past decade is probably unparalleled as a period of dynamic changes in the crop protection sciences-entomology, plant pathology, and weed science. These changes have been stimulated by the broad-based concern for a quality environment, by the hazard of intensified pest damage to our food and fiber production systems, by the inadequacies and spiraling costs of conventional crop protection programs, by the toxicological hazards of unwise pesticide usage, and by the negative interactions of independent and often narrowly based crop protection practices. During this period, the return to ecological approaches in crop protection was widely accepted, first within entomology and ultimately within the other crop protection and related disciplines. Integrated pest management is fast becoming accepted as the rubric describing a crop pro tection system that integrates methodologies across all crop protection dis ciplines in a fashion that is compatible with the crop production system. Much has been written and spoken about "integrated control" and "pest management," but to date no treatise has been devoted to the concept of "in tegrated pest management" in the broadened context as described above. Most of the manuscripts in this volume were developed from papers presented in a symposium at the annual meeting of the American Association for the Ad vancement of Science held in San Francisco in February, 1974. In arranging that symposium, the editors involved plant pathologists, entomologists, and weed scientists."

Pesticides have played a significant role in increasing food production, and in view of growing worldwide food demand we can expect the use of these chemicals to increase. However, some of them have found their way into the biosphere and have been classi fied as persistent toxic chemicals. This has resulted in serious concern about environmental contamination. Since we are going to continue using chemicals, we should learn more about such aspects as their transport in the environment, the relationship of their physical-chemical properties to transport, their persistence in the biosphere, their partitioning in the biota, and toxicological and epidemiological forecasting based on physical-chemical properties. Environmental chemodynamics is the name given to a subject which deals with some of the above topics, utilizing the principles of such disciplines as chemistry, physics, systems analysis, modelling, engineering, and medical and biological sciences. To ensure the safety of the environment, we must know more about the chemodynamical behavior of pesticides and related chemi cals. The purpose of the symposium "Environmental Dynamics of Pes ticides" was to explore the concept of chemodynamics as applied to pesticides and thus may help in developing the emerging field of environmental chemodynamics. The symposium was held during the l37th National American Chemical Society Meeting at Los Angeles, California, during April, 1974. The three sessions in the sym posium were chai'red by Drs. V.H. Freed, D.G. Crosby, and R. Haque."

The development of resistance to pesticides is generally acknowledged as one of the most serious obstacles to effective pest control today. Since house flies first developed resistance to DDT in 1946, more than 428 species of arthropods, at least 91 species of plant pathogens, five species of noxious weeds and two species of nematodes were reported to have developed strains resistant to on or more pesticides. A seminar of U. S. and Japanese scientists was held in Palm Springs, California, during December 3-7, 1979, under the U. S. -Japan Cooperative Science Program, in order to evaluate the status of research on resistance and to discuss directions for future emphasis. A total of 32 papers were presented under three principal topics: Origins and Dynamics of Resistance (6), Mechanisms of Resistance (18), and Suppression and Management of Resistance (8). The seminar was unique in that it brought together for the first time researchers from the disciplines of entomology, plant pathology and weed science for a comprehensive discussion of this common problem. Significant advances have been identified in (a) the development of methods for detection and monitoring of resistance in arthropods (electrophoresis, diagnostic dosage tests) and plant pathogens, (b) research on biochemical and physiological mechanisms of resis tance (cytochrome p450, sensitivity of target site, gene regulation), (c) the identification and quantification of biotic, genetic and operational factors influencing the evolution of resistance, and (d) the exploration of pest management approaches incorporating resis tance-delaying measures."

Aphids are the most important of the sap sucking insects, they are also major pests of agriculture, horticulture and forestry. This book covers the evolution of aphids and their development in relation to specific plants. Optimization is used to explain how modes of feeding and reproduction have affected their size and population structure and led to a very close and specific association with their host plants. Increasing knowledge of aphids has revealed that they are ideal organisms to use when studying many topical ecological issues. They are particularly important for testing predictions of life history theory, as their clonal structure makes it possible to test the response of a genotype to a wide range of conditions. Aphid Ecology has been thoroughly revised and expanded since the first highly successful edition was published in 1985. This book is aimed at specialists, post graduates and advanced undergraduates working in the fields of ecology and entomology.

P. T. N. SPENCER-PHILLIPS Co-ordinator, Downy Mildew Working Group of the International Society for Plant Pathology University of the West of England, Coldharbour Lane, Bristol BS16 1QY, UK Email: [email protected] It is a very great privilege to write the preface to the first specialist book on downy mildews since the major work edited by D. M. Spencer in 1981. The idea for the present publication arose from the Downy Mildew Workshop at the International Congress of Plant Pathology (ICPP) held in Edinburgh in August 1998. Our intention was to invite reviews on selected aspects of downy mildew biology from international authorities, and link these to a series of related short contributions reporting new data. No attempt has been made to cover the breadth of downy mildew research, but we hope that further topics will be included in future volumes, so that this becomes the first of a series following the five year ICPP cycle.

There is suf?cient need to document all the available data on biological control of rice diseases in a small volume. Part of this need rests on the global importance of rice to human life. In the ?rst chapter, I have tried to show that rice is indeed life for most people in Asia and shortages in production and availability can lead to a food crisis. While rice is cultivated in most continents, biological disease management attains special relevance to rice farmers of Africa, Asia, and also perhaps, Latin America. These farmers are resource-poor and might not be able to afford the cost of expensive chemical treatments to control devastating rice pathogens such as Magnaporthe oryzae (blast), Xanthomonas oryzae pv. oryzae (bacterial leaf blight), Rhizoctonia solani (sheath blight) and the virus, rice tungro disease. In an earlier volume that I developed under the title, Biological Control of Crop Diseases (Dekker/CRC Publishers, 2002), I included transgenic crops generated for the management of plant pathogens as biological control under the umbrella of a broad de?nition. Dr Jim Cook who wrote the Foreword for the volume lauded the inclusion of transgenic crops and induced systemic resistance (ISR) as a positive trend toward acceptance of host plant resistance as part of biocontrol. I continue to subscribe to this view.

Genetics and Genomics of Populus provides an indepth description of the genetic and genomic tools and approaches for Populus, examines the biology that has been elucidated using genomics, and looks to the future of this unique model plant. This volume is designed to serve both experienced Populus researchers and newcomers to the field. Contributors to the volume are a blend of researchers, some who have spent most of their research career on Populus and others that have moved to Populus from other model systems. Research on Populus forms a useful complement to research on Arabidopsis. In fact, many plant species found in nature are - in terms of the life history and genetics - more similar to Populus than to Arabidopsis. Thus, the genetic and genomic strategies and tools developed by the Populus community, and showcased in this volume, will hopefully provide inspiration for researchers working in other, less well developed, systems.

Pest Management Programs for Deciduous Tree Fruits and Nuts attempts to present the current status of pest management programs in orchard ecosystems. The book is a collection of papers from a symposium convened on the subject for the 1977 National Meeting of the Entomological Society of America and invitational papers on commodities not covered during the symposium. In recent years, books have appeared on "integrated pest management (IPM)"; however, most of these have concentrated on field crop IPM with an occasional chapter on fruits. No publication presently exists which brings together information on the pest management programs currently being conducted on the major nut crops, almonds, pecans and walnuts. Because it is the first treatment for almonds and walnuts, the authors of these chapters have attempted not only to present the current IPM technology but the historical data which led to the contemporary programs. Two chapters appear on pecan IPM. The first concentrates on the development of a management program for the pecan weevil, the key arthropod pest of pecans, while the second discusses the implementation of pilot pecan IPM programs in two southeastern states. The latter chapter illustrates that even with a limited data bank, the pesticide load in pecan orchards can be reduced by the adoption of the IPM approach to pest control.

PGPR have gained world wide importance and acceptance for agricultural benefits. These microorganisms are the potential tools for sustainable agriculture and the trend for the future. Scientific researches involve multidisciplinary approaches to understand adaptation of PGPR to the rhizosphere, mechanisms of root colonization, effects on plant physiology and growth, biofertilization, induced systemic resistance, biocontrol of plant pathogens, production of determinants etc. Biodiversity of PGPR and mechanisms of action for the different groups: diazotrophs, bacilli, pseudomonads, and rhizobia are shown. Effects of physical, chemical and biological factors on root colonization and the proteomics perspective on biocontrol and plant defence mechanism is discussed. Visualization of interactions of pathogens and biocontrol agents on plant roots using autofluorescent protein markers has provided more understanding of biocontrol process. Commercial formulations and field applications of PGPR are detailed.

Perhaps the best expression of our intent in organ z ng this gathering is found in the definition of the word colloquy and its derivations. A gathering allowing familiar and informal conversation among colleagues with similar interests was our objective. Our motives were, of course, complex. Our main intent was not, however, to add to the list of books competing for the time of the scientific community at-large. However, while informality was our objective, a lasting document exists in the form of this publication of the presentations forming the skeleton on which we built less formal but meatier communications. We hope you can reconstruct on these bones a perception of the state of the art in the subject at hand. The members of this assemblage are specialists in one or more subdisciplines. Their formal communications are found in texts and journals appropriate to their broader disciplines. Often their friends alone are privy to their less formal thoughts, intuitions, hopes, and especially fears and failures. We hoped by organizing this colloquium to develop familiar and informal conversation among those most interested and active in applying semiochemicals in pest control. That community, like others also shared by Gainesville entomologists, has little or no formal organization or means for assemblage. We proposed on this and future occasions to offer the opportunity to this and similar groups to gather, though we do not presume too much to lead but rather to facilitate conversation.

The growing body of information on bacteria pathogenic for humans, mammals and plants generated within the past ten years has shown the interesting conservation of newly identified genes that playa direct role in the pathogenic mechanism. In addition to these genes, there are also genes that confer host specificities and other traits important in pathogenesis on these pathogens. In this volume, we have organized the subject areas to best fit the concept on the way bacterial pathogens recognize, interact and invade the host, on the regulation of genes involved in virulence, on the genes involved in the elaboration of toxins and other pathogenic components such as iron sequestering proteins, and on the mechanisms of circumventing the host defense systems. These areas are divided into Sections. Section I covers the first step when the pathogen seeks its host, and Sections II through VI cover subsequent steps leading to pathogenesis while avoiding host defenses. We conclude this work with a chapter summarizing information on examples of virulence mechanisms that are highly conserved.

Microorganisms, including those genetically modified (GMOs), are increasingly being released deliberately into the environment for different purposes. One major interest is the use of antagonistic organisms for biological control of pests and plant diseases. Both in the development of biocontrol agents and their later risk assessment and product approval, there is a need for methods that facilitate monitoring of such introduced microorganisms. This book particularly addresses the various approaches for monitoring introduced fungi and the current status of techniques which may be relevant to use are described. Such techniques include marker genes and other DNA-based techniques, serology using polyclonals or monoclonals, the use of enzymes or secondary metabolite profiles, and electronic noses' as well as more traditional methods like dilution plating.

More than 270 scientists from 33 countries attended the 6th International Conference on Plant Pathogenic Bacteria in College Park, Maryland, June 2-7, 1985. The Conference was jOintly sponsored by the International Society of Plant Pathology, Bacteria Section and by the United States Department of Agriculture, Agriculture Research Service. The Conference provided an opportunity for the presentation and discussion of recent developments in phytobacteriology. The Conference was organized into five symposia, seven discussion sessions, contributed papers and poster presentations. More than 230 contributions were presented under the following topics: ice nucleating bacteria; detection, identification, nomenclature and taxonomy of phytopathogenic bacteria; applications and impact of new biotechnologies on phytobacteriology; bacterial phytotoxins; diagnostic phytobacteriology; management of bacterial plant diseases; and molecular biology, genetics and ecology, epidemiology of phytopathogenic bacteria. In addition, special sessions focused on Agrobacterium, Erwinia, Psedomonas and fastidious prokaryotes. This reflected the broad spectrum of current research activity in phytobacteriology. Furthermore, interest in this series of conferences clearly continues to increase. Key research scientists who are currently making major advances in phytobacteriology participated in the Symposia and Discussions. One of the most significant recent changes that has occurred in the field of plant pathology generally is the dynamic growth of research in which recombinant DNA technology is being applied in basic studies on bacterial plant pathogens. Results from investigations on the crown gall bacterium have stimulated expansion of research on other bacterial systems.

Plant pathology embraces all aspects of biological and scientific activity which are concerned with understanding the complex phenomena of diseases in plants. Physiological plant pathology represents those specialities within plant pathology which focus on the physiological and biochemical activities of pathogens and on the response of host plant tissues. Today there is an increasing recognition on the part of the scientific agri cultural community that only through a deeper and more fundamental under standing of all the interacting components of the agricultural biota can we expect to improve our capabilities of feeding an expanding world population. It is in this context that physiological plant pathology has assumed new significance within the broader field of plant pathology. No longer are studies on the biochemistry and physiology of pathogens and pathogenesis merely isolated academic exercises; rather, a substantial coherent body of knowledge is accumulating upon which our understanding of the process of disease developmen t and host resistance is being founded. It is from these foundations of knowledge that ultimately new insights into the control of plant diseases may be expected to grow. It seems appropriate, therefore, that at regular intervals those involved in the various subspecialities encompassing the broadest aspects of physiological plant pathology reassess the contributions within the particular specialities in the light of new knowledge and technologies for the purpose of articulating new and productive directions for the future."

Precise regulation of gene expression in both time and space is vital to plant growth, development and adaptation to biotic and abiotic stress conditions. This is achieved by multiple mechanisms, with perhaps the most important control being exerted at the level of transcription. However, with the recent discovery of microRNAs another ubiquitous mode of gene regulation that occurs at the post-transcriptional level has been identified. MicroRNAs can silence gene expression by targeting complementary or partially complementary mRNAs for degradation or translational inhibition. Recent studies have revealed that microRNAs play fundamental roles in plant growth and development, as well as in adaptation to biotic and abiotic stresses. This book highlights the roles of individual miRNAs that control and regulate diverse aspects of plant processes.

Proceedings of a Meeting of the IUFRO, Working Party on Root Physiology and Symbiosis

Plant growth and development is controlled by various environmental cues that are sensed by the plant via various signal transduction pathways coupled to specific response. Some of these pathways are conserved from yeast to plants being regulated by various kinases and phosphatases. In addition, plants have many unique pathways that transduce to specific signals such as light, phytohormones and oligosaccharides. This volume highlights some of the examples of the plant signal transduction machinery opening new vistas in research on plant growth and development. The new technologies including the use of bacteria, yeast and Arabidopsis as functional complementation systems are providing proof of function of many of the proteins that show homology to those from other organisms. These studies will eventually lead to improvement of crop plants and use of plants as a new resource for producing desirable products to meet the growing needs of mankind.

The fifth meeting of scientists working with Frankia and actinorhizal plants was held at Montmorency Forest of Laval University in Quebec from August 6-8, 1984. Results of research presented at the meeting are included in this special volume of Plant and Soil. The understanding of actinorhizal systems continue to increase, though work and use shops and discussions at this and similar meetings make it evident that this important subject remains open for fruitful investigation at all levels. Some important 'firsts' were reported at this meeting. The first extensive survey of Frankiae and their host specificity ranges from Asia was presented. This is of significance since Asia is a center of diversity for many actinorhizal host plant genera. A report that proto plasts of Frankia have been produced and regenerated for the first time improves the possibility for genetic manipulation of Frankia. It is also important to note the first report herein of successful mass inoculation of actinorhizal plants commercially for stabilization and reclamation of disturbed soils around hydroelectric power projects in Quebec. This heralds the transfer of actinorhizal technology to private and public users. The bacterial genus Frankia is easily recognized both in vivo and in vitro, and isolation of this organism has become routine. But, as yet, there are not sufficient biochemical, morphological, or anatomical criteria for establishing species."

To meet the challenge of feeding ever increasing human population, efficient, economical and environment friendly disease control methods are required. Pests are responsible for heavy crop losses and reduced food supplies, poorer quality of agricultural products, economic hardship for growers and processor. Generally, chemical control methods are neither always economical nor are they effective and may have associated unwanted health, safety and environmental risks. Biological control involves use of beneficial microorganism to control plant pathogens and diseases they cause and offers an environmental friendly approach to the effective management of plant diseases. This book provides a comprehensive account of interaction of host and its pathogens, induced host resistance, development of biological control agents for practical applications, the underlying mechanism and signal transduction. The book is useful to all those working in academia or industry related to crop protection.

The Proceedings of the 4th International Symposium held by the European Foundation for Plant Pathology on Diagnosis and Identification of Plant Pathogens in Bonn, Germany, from September 9th to 12th, 1996, include information on the application of classical as well as novel and innovative methods and techniques. This book gives an overview of the recent status and trends in the diagnosis and identification of viruses, bacteria and fungi in plants. It covers not only the development of methods and application of techniques but also its transformation into practice for disease-forecasting systems. The book includes 58 oral presentations and 61 poster contributions covering 6 main topics. In addition to introductory overviews of the phytosanitary implications of diagnosis in integrated crop protection, the application of classical and innovative diagnostic methods is stressed. The other contributions cover taxonomy and differentiation of plant pathogens, serological assays, nucleic acid based hybridisation techniques, disease assessment and quantification as well as disease prognosis and expert systems. This book provides information for all researchers and scientists involved in the production of healthy crop plants. It is of special interest for plant pathologists with responsibilities in the fields of plant quarantine, extension and applied diagnosis of plant pathogens as well as for those working in research and development of innovative crop protection techniques.

Plants interact with a large number of microoganisms which have a major impact on their growth either by establishing mutually beneficial symbiotic relationships or by developing as pathogens at the expense of the plant with deleterious effects. These microorganisms differ greatly not only in their nature (viruses, phytoplasmas, bacteria, fungi, nematodes, ... ) but also in the way they contact, penetrate and invade their host. Histology and cytology have brought an essential contribution to our knowledge of these phenomena. They have told us for instance, how specialized structures of the pathogen are often involved in the adhesion and penetration into the plant, how the interface between both organisms is finely arranged at the cellular level, or what structural alterations affect the infected tissues. They have thus set the stage for the investigations of the underlying molecular mechanisms could be undertaken. Such investigations have been remarkably successful in the recent years, expanding considerably our understanding of plant-microorganism interactions in terms of biochemical changes, rapid modifications of enzymatic activities, coordinated gene activation, signal reception and transduction. Biochemistry, molecular biology and cellular physiology have taken precedence in the phytopathologist's set of methods.