Research on the mechanisms of plant defense responses to stress and pathogen attack has attracted much attention in recent years. This increasing interest stems from the fact that the tools of molecular biology now enable us to study the molecular basis of old biological concepts such as host-pathogen recognition (and particularly the gene for-gene relationship), hypersensitive cell death and systemic acquired resistance. Our knowledge about avirulence and resistance genes, elicitors, signal transduction and genes involved in plant defense is rapidly expanding. Moreover we are just beginning to test in planta the potential of these results for biotechnological applications, aimed at improving plant resistance to diseases. The 2nd Conference of the European Foundation for Plant Pathology, hosted by the "Societe Fran~aise de Phytopathologie", was devoted to "Mechanisms of plant defense responses" and was held in Strasbourg, France. It brought together over 350 scientists from universities, research institutes and private sectors of 24 countries. Major advances in the areas under study have been reviewed in plenary lectures and are developed in the main articles of this book. Over 160 high-quality posters were presented and are summarized in short articles. Data from outstanding posters, which were discussed after a short oral presentation, are found in extended articles. As a whole the book presents a collection of papers arranged in six sections and reflecting the present day state-of-the-art of research in the field of plant defense reactions.

In 1992 a Concerted Action Programme (CAP) was initiated by Peter Sijmons with the purpose of intensifying collaborations between 16 European laboratories working on plant-parasitic nematodes. The four-year programme entitled Resistance mechanisms against plant-parasitic nematodes' focused on molecular aspects of the interaction between sedentary nematodes and plants on the model system Arabidopsis and on novel resistance strategies. Funding was provided mainly for exchange visits between collaborating laboratories and for the organization of annual meetings. During the last annual meeting which was held in May 1996 in Toledo, Spain, Carmen Fenoll initiated the production of this volume. The book presents a series of up-to-date reviews, each written by one of the participating laboratories, which include the scientific progress achieved in the frame of this CAP but are by no means limited in scope to this work.

When I received an invitation to attend the International Symposium on Lethal Yellowing being organised by the Centro de Investigacion Cientifica de Yucatan (CICy), I was excited and a little nostalgic. During the 1970s, a series of similar symposia had been held under the auspices of the loosely-constituted "International Council on Lethal Yellowing" (ICL Y). These were the years when the MLO cause for L Y was first proposed, a vector was found, the disease was racing across mainland Florida, USA and it was suspected of having jumped to Cozumel. Analogous diseases were also reported to be spreading in Africa and elsewhere. The ICL Y meetings, held approximately every two years, proved to be an immensely valuable forum for all involved in the research and control of L Y. They attracted a very wide cross-section of scientists and practitioners working on L Y, on related diseases, and on palms in general. Many participants of those ICL Y meetings also attended this CICY Symposium. Unfortunately, during the 1980s, as countries learned to live with L Y, most of the national and international funding for L Y research dried up, and so did ICL Y. The present symposium is the only international meeting to have been devoted to L Y since the last meeting of rCLY in 1979. Its convening in Merida is timely.

The protection of agricultural crops, forest, and man and his domestic animals from annoyance and damage by various kinds of pests remains a chronic problem. As we endeavor to improve pro duction processes and to develop more effective and acceptable tactics for achieving this protection, we must give high priority to all potentially useful techniques for the control and management of insects. Pest control is recognized as an acceptable and necessary part of modern agriculture. Methods employed vary greatly and tend to reflect compromises involving 3 determining factors: technological capability, economic feasibility, and social acceptability. How ever, these factors are also subject to change with time since each involves value judgments that are based on available information, cost, benefit considerations, the seriousness of the pest problem, and the political climate. Whatever method is chosen, energy resources continue to dwindle under the impact of increasing popu lation, and it is inevitable that greater reliance must be placed upon renewable resources in pest management. One alternative is the use of a pest management method that uses the energy of the pest's own biomass to fuel a self-perpetuating control system. The use of biological control agents for the control of pests has long been an integral part of the pest management strategy in crop production and forestry and in the protection of man and animals. The importance and unique advantages of the method are well recognized; numerous treatises deal with accomplishments and methodologies."

These Proceedings evolved from the OECD Co-operative Research Programme workshop on "Potential ecological impact of transgenic plants expressing viral sequencies," held at the Agricultural Biotechnology Center in Godollo, Hungary on 24-26 April 1997. The OECD Co-operative Research Programme At the Directorate for Agrieulture of the Organisation for Economie Co-operation and Development (OECD) a co-operative research programme for "Biological Resource Management" has existed since 1990. It foeuses on work in four specific topie areas, one of whieh is "Ecology and utilisation of new organisms" (Theme 3). The activities promoted by this programme are post-doctoral fellowships (announced annually), and the organisation of expert workshops (1-2 workshops per Theme per year). The 26 OECD member countries participating in this programme are: Australia, Austria, Belgium, Canada, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, ltaly, Korea, Japan, the NetherIands, New Zealand, Norway, Poland, Portugal, Spain, Sweden, SwitzerIand, Turkey, the UK, and the USA."

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.

Only 14 years have passed since the first publication appeared which implicated mycoplasmas as agents of plant disease. The diseases them selves have been known for much longer; indeed clover phyllody, a typical example, was described in the seventeenth century, well before any animal mycoplasma diseases had been documented. The early history of plant mycoplasmas is described in Chapter 2 and one obvious conclusion to be drawn from the frustrating experiences of the earlier workers is that the experimental methods at their disposal were simply inadequate for the task. Progress in science depends critically upon the development of new methods. Although important advances have been made in plant and insect mycoplasmology, notably in the discovery of spiroplasmas, many intractable problems remain. Most plant myco plasmas cannot yet be cultured in vitro, and their natural plant habitat, the phloem, is one of the most difficult plant tissues for the experi menter to handle, placing severe restrictions on the type of experiments which can be performed in vivo. It is clear that radically new methods may be required to solve these problems. A survey of the progress which has been made shows that application of techniques from a wide range of disciplines has been necessary. A successful individual or group of workers must possess the skills of a plant pathologist, a plantsman, a plant physiologist, a light-and electron microscopist, a bacteriologist, a biochemist, an immunologist, an ento mologist, a virologist and a molecular geneticist."

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.

It was a compliment to me to be asked to prepare the fourth edition of Westcott's Plant Disease Handbook, and the decision to accept the responsi bility for the fourth edition and now the fifth edition was not taken lightly. The task has been a formidable one. I have always had a great respect professionally for Dr. Cynthia Westcott. That respect has grown considerably with the completion of the two editions. I now fully realize the tremendous amount of effort expended by Dr. Westcott in developing the Handbook. A book such as this is never finished, since one is never sure that everything has been included that should be. I would quote and endorse the words of Dr. Westcott in her preface to the first edition: "It is easy enough to start a book on plant disease. It is impossible to finish it. " This revision of the Handbook retains the same general format contained in the previous editions. The chemicals and pesticides regulations have been updated; a few taxonomic changes have been made in the bacteria, fungi, and mistletoes; the changing picture in diseases caused by viruses and/or viruslike agents has been described. A few new host plants have been added, and many recently reported diseases as well as previously known diseases listed now on new hosts have been included. In addition, photographs have been replaced where possible, and the color photograph section has been retained.

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."

Chemical defence by means of toxins poisonous to other organisms, be they animals or plants, is widespread amongst the plant kingdom - including microorganisms as well. This book embraces the analysis of a wide range of plant toxins and this fills a gap in the plant pathology and ecological biochemistry fields. The topics covered include toxic extracellular enzymes, host selective toxins, elicitors, phototoxins, aflatoxins, mycotoxins, and ecotoxic substance tests by pollen germination and growth. The analytical procedures, which are used to evaluate the toxins, are covered in such a way that the reader is able to carry them out mostly solely by following the detailed descriptions.

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."

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.

In the past half century, filamentous fungi have grown in commercial importance not only in the food industry but also as sources of pharmaceutical agents for the treatment of infectious and metabolic diseases and of specialty proteins and enzymes used to process foods, fortify detergents, and perform biotransformations. The commercial impact of molds is also measured on a negative scale since some of these organisms are significant as pathogens of crop plants, agents of food spoilage, and sources of toxic and carcinogenic compounds. Recent advances in the molecular genetics of filamentous fungi are finding increased application in the pharmaceutical, agricultural, and enzyme industries, and this trend promises to continue as the genomics of fungi is explored and new techniques to speed genetic manipulation become available. This volume focuses on the filamentous fungi and highlights the advances of the past decade, both in methodology and in the understanding of genomic organization and regulation of gene and pathway expression.

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.

The explosive increase in the world's human population, with conse quent need to feed an ever-increasing number of hungry mouths, and the largely resultant disturbances and pollution of the environment in which man must live and produce the things he needs, are forcing him to search for means of solving the first problem without intensifying the latter. Food production requires adequate assurance against the ravages of insects. In the last three decades short-sighted, unilateral and almost exclusive employment of synthesized chemicals for insect pest control has posed an enormous and as yet unfathomed contribution to the degradation of our environment, while our insect pest problems seem greater than ever. Properly viewed, pest control is basically a question of applied ecology, yet its practice has long been conducted with little regard to real necessity for control, and in some cases, with little regard to various detrimental side-effects or long-term advantage with respect, even, to the specific crop itself. This book deals fundamentally with these questions. The development of pesticide resistance in many of the target species, against which the pesticides are directed, has occasioned an ever-increasing load of applications and complexes of different kinds of highly toxic materials. This has been made even more "necessary" as the destruction of natural enemies has resulted, as a side effect, in the rise to pest status of many species that were formerly innocuous. The application of broad-spec trum pesticides thus has many serious and self-defeating features.

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.

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.

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.

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.

For investigators engaged in the study of toxins generally, and host-specific toxins in particular, it is a rare treat to attend a meeting in which toxins involved in plant pathogenesis are emphasized. A gathering of this type provides opportunity to consider the discovery of new toxins, their chemical structures, genes encoding enzymes that control their biosyntheses, their sites of action and physiological effects on plants, and their roles (if any) in pathological processes. Having acknowledged the inspiration fostered by a 'toxin meeting', however, it is important to point out that the program of this symposium was generously sprinkled with 'nontoxin' talks. These contributions generated cross-disciplinary discussion and promoted new ways of thinking about relationships among factors required for plant disease development. The point can be illustrated by considering just one example. We have in the past often regarded diseases mediated by host-specific toxins and diseases involving 'gene-for-gene' relationships as representing two different classes of fungal/plant interaction. This is largely because the key molecular recognition event in so-called 'toxin' diseases leads to compatibility, whereas the corresponding event in 'gene-for-gene' diseases leads to incompatibility. Yet the race specific elicitors produced by the 'gene-for-gene' fungi Cladosporium fulvum (De Wit, Adv. Bot. Res. 21:147- 185, 1995) and Rhynchosporium secalis (Rohe et a1. , EMBO J.

Potato is the fourth major staple food in the world and is still rapidly gaining importance, especially in the tropics. In May, 1994 the second international potato modelling conference was held in Wageningen, the Netherlands, as a summerschool of the C. T. de Wit Graduate School. The conference was sponsored by DLO, SCRI, SSCR, W AU and the LEB-Fund. Over 80 scientists participated, coming from 16 countries. Of each crop physiological and modelling subject, a leading scientist was requested to write a review of the most recent developments in his or her field. The reviews, with highlights from the authors' own work, are such that the physiological work described is of interest to the modeller and the modelling work to the crop physiologist. Applications of the quantitative approach are also reviewed in the concluding chapters that deal with decision support systems, breeding and agro-ecological zoning. An outstanding point of this book is that both the crop ecology and the modelling of a broad range of biotic and abiotic factors are treated by scientists representing groups which are specialized in the subject. The two related disciplines met during the conference and thus wrote the chapters with each other's interest in mind. The book highlights the limitations for potato growth and development from the viewpoints of both the crop physiologist and the crop-systems analyst.

During the last decade, research on Pseudomonas syringae pathovars and related pathogens has progressed rapidly, opening up many new avenues. The application of molecular genetics has provided new insights into determinants of pathogenicity and virulence. Progress has also been made in elucidating the chemical structures and modes of action of phytotoxins from Pseudomonas syringae; by establishing novel strategies for disease control; in biotechnological applications; by studying the resistant reaction of the plant with a combined biochemical and genetic approach; and in the development of new detection and identification methodologies as tools in epidemiological studies. With such rapid advances it becomes more and more difficult to keep abreast of the developments and concepts within disciplines, all involving research on pathovars of P. syringae. In an attempt to provide a balanced overview, recent developments in these rapidly expanding fields have been critically reviewed at the beginning of each chapter by internationally renowned experts. Our comprehensive coverage has been made possible because all the contributors to this volume presented their latest findings at the 5th International Conference on Pseudomonas syringae Pathovars and Related Pathogens' in Berlin, September 3-8, 1995. In this way, it was possible to bring together contributions from a wide range of fields including phytopathology, genetics, bacteriology, plant breeding, plant protection, and taxonomy. This book is not intended simply as a record of the proceedings of the Berlin Conference, but as an extension of recent findings and hypotheses put forward at the meeting. All papers published in this volume have been reviewed by the Editors.

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.

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."