Biological Control of Plant Diseases Progress and Challenges for the Future NATO ASI Series Advanced Science Institutes Series A series presenting the results of activities sponsored by the NATO Science Committee, which aims at the dissemination of advanced scientific and technological knowledge, with a view to strengthening links between scientific communities. The series is published by an international board of publishers in conjunction with the NATO Scientific Affairs Division A Life Sciences Plenum Publishing Corporation B Physics New York and London C Mathematical and Physical Sciences Kluwer Academic Publishers D Behavioral and Social Sciences Dordrecht, Boston, and London E Applied Sciences F Computer and Systems Sciences Springer-Verlag G Ecological Sciences Berlin, Heidelberg, New York, London, H Cell Biology Paris, Tokyo, Hong Kong, and Barcelona I Global Env.ironmental Change Recent Volumes in this Series Volume 224-Drug Epidemiology and Post-Marketing Surveillance edited by Brian L. Strom and Giampaolo Velo Volume 225-Computational Aspects of the Study of Biological Macromolecules by Nuclear Magnetic Resonance Spectroscopy edited by Jeffrey C. Hoch, Flemming M. Poulsen, and Christina Redfield Volume 226-Regulation of Chloroplast Biogenesis edited by Joan H. Argyroudi-Akoyunoglou Volume 227-Angiogenesis in Health and Disease edited by Michael E. Maragoudakis, Pietro Gulli no, and Peter I. Lelkes Volume 228-Piayback and Studies of Animal Communication edited by Peter K. McGregor Volume 229-Asthma Treatment-A Multidisciplinary Approach edited by D. Olivieri, P. J. Barnes, S. S. Hurd, and G. C. Folco Volume 230-Biological Control of Plant Diseases: Progress and Challenges for the Future edited by E. C. Tjamos, G. C. Papavizas, and R. J. Cook Series A: Life Sciences Biological Control of Plant Diseases Progress and Challenges for the Future Edited by E. C. Tjamos Agricultural University of Athens Athens, Greece G. C. Papavizas Agricultural Research Service U.S. Department of Agriculture Beltsville, Maryland and R.J.Cook Agricultural Research Service U.S. Department of Agriculture Pullman, Washington Springer Science+Business Media, LLC Proceedings of a NATO Advanced Research Workshop on Biological Control of Plant Diseases: Progress and Challenges for the Future, held May 19-24, 1991, in Cape Sounlon, Athens, Greece NATQ-PCO·DATA BASE The electronic index to the NATO ASI Series provides full bibliographical references (with key words and/or abstracts) to more than 30,000 contributions from international scientists published in all sections of the NATO ASI Series. Access to the NATO-PCO-DATA BASE is possible in two ways: -via online FILE 128 (NATO-PCO-DATA BASE) hosted by ESRIN, Via Galilee Galilei, 1-00044 Fr ascati, Italy. -via CD-ROM "NATO-PCO-DATA BASE" with user-friendly retrieval software in English, French, and German(© wrv GmbH and DATAWARE Technologies, Inc. 1989) The CD-ROM can be ordered through any member of the Board of Publishers or through NATO PCO, Overijse, Belgium. L1brary of Congress Catalog1ng-1n-Publ1cat1on Data Biological control of plant diseases , progress and challenges for the future I edited by E.C. Tjamos, G.C. Papavizas, and R.J. Cook. p. em. -- <NATO AS! series. Series A, Life sciences ; v. 230) Includes bibliographical references and index. ISBN 978-1-4757-9470-0 ISBN 978-1-4757-9468-7 (eBook) DOI 10.1007/978-1-4757-9468-7 1. Phytopathogenic microorganisms--Biological control--Congresses. 2. Microbial pesticides--Congresses. 3. Plant diseases--Congresses. I. T;amos, E. C., 1943- II. Papavizas. George Constantine. 1922- III. Cook, R. James, 1937- IV. Series. SB732.6.B582 1992 632 .96--dc20 92-10740 CIP ISBN 978-1-4757-9470-0 © 1992 Springer Science+Business Media New York Originally published by Plenum Press, New York in 1992 Softcover reprint of the hardcover 1st edition 1992 All rights reserved No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher PREFACE 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. The ARW began with a consideration of naturally occurring, resident biological control or'ganisms and how the benefits of these organisms might be enhanced or at least conserved by cultural or farming practices. The ARW then consider'ed biological control with agents introduced into the phyl loplane, rhizosphere, or soil. Whereas biological control of insect pests commonly involves foreign exploration and importation of natural enemies of the insect, obtained from the original "home" of the insect, biological control of plant pathogens and plant parasitic nematodes commonly involves the enhancement or augmentation of antagonists already present on the plant or in the soil but at populations too low to provide adequate or timely bio logical control. Major attention was given on the third day to mechanisms of biological control, particularly as revealed by recent approaches with molecular biology and genetics. Overcoming some of the histor'ical con straints to biological control with microorganisms may well depend on moving beyond the use of naturally occurring strains and turning instead to strains that have been genetically improved to match specific needs and environments, as has already been done in industrial microbiology and plant breeding. The workshop then considered formulation, delivery, tracking and regulations of natural and genetically modified microbial biocontrol agents, and finally, on the fifth day, strategies for making greater use of biological control of plant diseases and nematodes. The ARW focused almost entirely on microorganisms as biological control agents, including the use of microorganisms closely related to pathogens and avirulent or dsRNA-infected ("hypovirulent") strains of the pathogen itself for biological control. The use of microorganisms for biological control presents many unique challenges as well as opportunities, whether managed as resident communities or introduced as individual or mixtures of strains. In addition to the scientific and technical challenges, the regulatory process in most countries, including NATO countries, requires special reviews and tests prerequisite to the registration of these agents as "microbial pesticides" if introduced and intended for biological control. This book addresses the entire range of challenges and opportunities, from discovery to implementation. v The organization and running of a NATO ARW requires extensive planning and the efforts of many people. The idea to propose this particular ARW grew out of informal discussions during the 5th International Congress of Plant Pathology in Kyoto, Japan in August, 1988. An Organizing Committee was then formed in June, 1989, with E. c. Tjamos as Director and Local Organizer, R. J. Cook and G. C. Papavizas as Co-Directors, and Claude Alabouvette, J. M. Lynch, and B. Schippers as members. In addition to the Organizing Committee, special thanks are also due to those who chaired the sessions, to Mrs Marina Tjamos for her skillful assistance with local arrangements, and Miss Emily Pantazi for preparing the final typescripts of all the papers from which this volume was produced. We especially thank the Scientific Affairs Division of NATO for sponsoring the ARW and for the financial support provided by this Division for travel of the invited speak ers and other participants. Throughout the week of the ARW, the participants worked to identify issues as well as concepts, and to come up with recommendations for consider ation in NATO countries, or in all countries interested in furthering the use of biological control. The final list of consensus statements was developed by R. J. Cook, D. Hornby, G. C. Papavizas, J. M. Lynch, R. K. S. Wood, J. Kuc, and K. A. Powell and follows under the heading Conclusions and Recommendations. This list was developed in consideration of better understanding among individual investigators, government funding agencies, industry, academia, regulatory agencies, and others regarding needs, opportunities, and challenges in the field of biological control applied to plant diseases and plant parasitic nematodes. E. C. Tjamos, Athens G. c. Papavizas, Beltsville R. J. Cook, Pullman CONCLUSIONS AND RECOMMENDATIONS 1. NATO countries are urged to increase their efforts in research on the development and implementation of biological control for the many plant diseases and plant parasitic nematodes important in current production systems for which there are no economically or environmentally accept able methods of control available at present or likely to be available in the future. 2. The cost of regulatory and efficacy testing for chemicals has made some small markets, including markets represented by one disease or one nematode problem for one crop, inaccessible to chemical control. Bio logical control is ideally suited for use in these situations, but its development requires considerable well-financed research in order to produce reliable, consistent, and efficacious products. 3. Microorganisms with potential to provide effective and useful biological control of plant diseases and plant parasitic nematodes already exist on or within most plants or soils as part of a vast and largely untapped natural biological and genetic resource. 4. Greater use can be made of microorganisms in natural biological control, either through management of microbial communities and natural cycles with farming practices or by isolation and reintroduction (augmentation) of particularly good strains as formulated products. 5. Biological control agents tend to be highly specific and selective in the pathogens or nematodes the control and the environments or sites in which they are effective. Because of this, the number of different species or strains of biological control agents needed as formulated products to control the many plant diseases and nematodes on the diver sity of crops, across the wide range of agricultural and foresty environ ments, will be considerably larger compared with the number of chemicals that might be required to control the same problems. 6. While consistent with natural control, and analogous to the current use of tens, hundreds, or even thousands of cultivars of the same crop world wide, an approach to biological control that depends on the use of large numbers of different environment-specific microorganisms cannot succeed with regulatory policies that require separate approval for each strain, improved strain, or strain mixture and where the protocols for registra tion are based on those developed for chemicals. 7. The issues that must be addressed before introducing microorganisms into an environment are of particular relevance to programs on biological control of plant diseases and plant parasitic nematodes; other than the use of plants genetically modified, managed, or induced to express dis ease or nematode resistance, virtually all biological control agents of plant diseases and nematodes are and will be mi~roorganisms. 8. The high degree of specificity and selectivity characteristic of bio logical control agents offers many proven advantages in environmental and consumer safety. While m~croorganisms as biological control agents raise certain unique questions regarding safety, the participants of this ARW noted that in the 70 years since the first attempts at biological control of plant diseases with introduced microorganisms, so far no experimental test or commercial use has led to a new disease or pest problem caused by the introduced biological control agent. 9. Plant- and soil-associated biological control agents should not present an unusual or significant risk to the environment when reintroduced to augment their populations in the same or similar habitats from which they were isolated and where they occur naturally. Any nontarget ecological effects of such introductions are probably no greater and are more likely to be orders of magnitude smaller than the ecological effects of common cultural practices such as rotating crops, tilling soils, or incorporating green manures or barnyard manure into soils. 10. Many uses of microbial biological control agents against plant diseases and plant parasitic nematodes will be small-scale, because of the speci ficity and selectivity of natural strains. Such uses could provide opportunities for small businesses or local industries, but even these enterprises are likely to succeed only with assistance from public-sup ported institutions in registration and implementation. viii CONTENTS ENRICHMENT, CONSERVATION AND MANAGEMENT OF BIOLOGICAL CONTROL BY RESIDENT SOIL- AND PLANT-ASSOCIATED MICROORGANISMS Selective elimination of soilborne plant pathogens and enhancement of antagonists by steaming, sublethal fumigation and soil solarization [R]* ...•.•..•....•... E.C. Tjamos Biological control of plant parasitic nematodes [R]* •.•....•..•.••..• 17 F.L. Lamberti and A. Ciancio Prospects for management of natural suppressiveness to control soilborne pathogens [R]* .•.•.....•....•...•......•.• 21 B. Schippers Use of agricultural and municipal organic wastes to develop suppressiveness to plant pathogens [R]* ..•............•. 35 A. Tranker Leaf and blossom epiphytes and endophytes as biological control agents [R] *............................................. 43 A. Tronsmo The weakening effect as a trigger for biological control and criteria for its evaluation [R]* ..................•.•.....•• 55 J. Katan, C. Ginzburg and S. Freeman Integrated control of Verticillium wilt of cotton by soil solarization and tolerant cultivars [r]* ............•.•........• 63 M.A. Blanco-Lopez, R.M. Jimenez-Diaz, J.M. Melero-Vara and J. Bejarano-Alcazar Evaluation of soil solarization for the control of Fusarium wilt of tomato [r]* ...........................................•. 69 H. Oliveira Evaluation of soil solarization singly or in combination with fungal or bacterial biocontrol agents to control Fusarium wilt of carnation [r]* ................................. 75 K. Elena and E.C. Tjamos * [R]-Review paper * [r]-Research paper ix