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Neotyphodium/Grass Interactions
Neotyphodium/Grass Interactions
Edited by
Charles W. Bacon United States Department of Agriculture
Athens, Georgia
and
Nicholas S. Hill The University of Georgia
Athens, Georgia
Springer Science+Business Media, LLC
Library of Congress Cataloglng-In-Publlcatlon Data
Neotyphodium/grass interactions I edited by Charles W. Bacon and Nicholas S. Hill.
p. cm. "Proceedings of the third International Symposium on
Acremon ium/Grass Interact ions, he ld May 28-31, 1997, in Athens, Georgia"--T.p. verso.
Includes bibliographical references and Index. ISBN 978-1-4899-0273-3 ISBN 978-1-4899-0271-9 (eBook) DOI 10.1007/978-1-4899-0271-91. Neotyphodium--Congresses. 2. Epichloe--Congresses.
3. Grasses--Ecophyslology--Congresses. 4. Endophytic fungl--Congresses. 5. Plant-fungi relationships--Congresses. I. Bacon, Charles W. II. Hill, Nicholas S. (Nicholas Scott) III. International Symposium on Acre.onium/Grass Interactions (3rd , 1997 , Athens, Ga.) OK623.C55N46 1997 579.5'67--dc21 97-17157
CIP
Proceedings of the Third International Symposium on Acremonium/Grass Interactions, held May 28 - 31, 1997, in Athens, Georgia
ISBN 978-1-4899-0273-3
© 1997 Springer Science+Business Media New York Originally published by Plenum Press, New York in 1997
Soflcover reprint of the hardcover 1 st edition 1997
http://www.plenum.com
10987654321
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,
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PREFACE
Endophytic fungi belonging to the Balansieae tribe were first hypothesized to cause poor livestock performance in 1977 and, in 1980, the association was validated. The fungi were extensively studied and classified according to morphology, their life cycles examined to determine methods to eliminate the fungi in grasses, and practical methods developed for livestock producers to eliminate endophyte-infected plants from pastures and establish endophyte-free plants. Hindsight illustrates how primitive was our understanding of the associations between endophyte, grass plant, and animal. The plant/endophyte associations, thought to be rare cases, have now been identified in grasses that are adapted from tropical to nearly arctic, and from marshland to desert climatic regimes.
In the two decades that have passed since the first endophyte-plant-animal association was made, the scientific community has re-classified the endophytic fungi twice (now the genus Neotyphodium), ~he systematics and ecological role of endophytes have been more clearly defined, endophytes and grasses are now generally accepted as mutualistic symbionts, the chemistry of toxins and their functions defined, beneficial effects of endophytes on plants identified, and commercial ventures have emerged based upon endophyte research in the turfgrass and livestock industries.
Initial research efforts were principally conducted in the United States and New Zealand because of the significance of endophytes to the respective livestock industries, but have since expanded to all six of the habitable continents. Clearly, new technologies have permitted more efficient and more specific hypothesis testing to define the structural and functional interactions within natural and artificial ecosystems containing endophyte-infected grasses, and there has been a virtual explosion of research literature on the subject.
Perhaps the greatest challenge for researchers and end-users of technology is to appreciate, and be current on, the breadth of literature associated with mutualistic endophytes in grasses. The objective in organizing this book was to provide readers with current reviews and examples (short papers) of basic and applied research on the ecology and systematics of grass-endophyte associations, commercial uses of endophytes for livestock and turf industries, the pathophysiology of toxicoses in livestock, cellular and molecular techniques available for investigative research, and current farm practices used to avert or ameliorate livestock toxicosis syndromes. The editors and organizers of the 3rd Symposium, held on the University of Georgia's campus, hope that understanding these
v
vi Preface
research areas will lead to sustainable strategies in which endophytes are viewed and used as beneficial components of natural and man-made grassland ecosystems.
Charles W. Bacon Agricultural Research Service, USDA Nicholas S. Hill Department of Crop and Soil Sciences University of Georgia
ACKNOWLEDGMENTS
The generosity of the following organizations is greatly appreciated for their financial support in helping defer costs associated with organizing and running the Symposium from which this book was developed. We gratefully acknowledge the untiring efforts of the members of the Program Committee and extend special appreciation to the staff on the Arrangement Committee, the Georgia Center of Continuing Education, for facilitating the 3rd Symposium held at the University of Georgia.
The University of Georgia, Office of the Vice President for Academic Affairs, Athens, GA The Agricultural Research Service, USDA, Washington, DC The USDA National Research Initiative Competitive Grants Program, Washington, DC Pennington Seed, Inc., Oregon Division, Lebanon, OR Turf Seed Testing, Hubbard, OR Pure Seed Testing, Hubbard, OR Advanta Seeds West, Inc., Albany, OR The Upjohn Company, Kalamazoo, MI International Seeds, Inc., Halsey, OR New Jersey Turfgrass Association, NJ
Program Committee
C. W. Bacon, USDA, ARS J. H. Bouton, University of Georgia N. S. Hill, University of Georgia C. S. Hoveland, University of Georgia J. K. Porter, USDA, ARS 1. Stuedemann, USDA, ARS F. N. Thompson, Jr., University of Georgia
vii
CONTENTS
Introduction: Welcome and a Bit of Endophyte History Carl S. Hoveland
1. An Overview of Neotyphodium-Grass Interactions ....................... . G. C. M. Latch
2. The Evolution of Mutualism in Grass-Endophyte Associations Heather H. Wilkinson and Christopher L. Schardl
3. Systematics of the Graminicolous Clavicipitaceae: Applications of
xv
13
Morphological and Molecular Approaches ......................... 27 James F. White, Jr.
4. Application of Endophyte Allozyme Analysis to Lolium perenne Population Ecology in Hill Country Pasture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
D. J. Barker, M. J. Christensen, and Christie Wever
5. Endophyte Compatibility in Perennial Ryegrass, Meadow Fescue, and Tall Fescue: A Short Review ........................................ 45
M. J. Christensen
6. Acremonium Endophytes in Mediterranean Tall Fescue .................... 49 S. L. Clement, W. Graves, P. Cunningham, V. Nebling, W. Bounejmate,
S. Saidi, B. Baya, M. Chakroun, A. Mezni, and C. Porqueddu
7. Distribution of Ergot Alkaloids within the Family Clavicipitaceae . . . . . . . . . . . . 53 A. E. Glenn and C. W. Bacon
8. Quantitative Assessment of in Planta Distribution of Metabolic Activity and Gene Expression of Neotyphodium Endophytes ..................... 57
S. Herd, M. J. Christensen, K. Saunders, B. B. Scott, and J. Schmid
9. Increases in Endophyte Incidence in Perennial Ryegrass at Palmerston North, Manawatu, New Zealand ....................................... 61
D. E. Hume and J. L. Brock
10. Ergovaline Distribution in Perennial Ryegrass Naturally Infected with Endophyte 65 G. A. Lane, O. J. P. Ball, E. Davies, and C. Davidson
ix
x Contents
11. A Survey of Endophytic Fungi in Some Native Forage Grasses of Northwestern China ...................................... , . . . ... . .. . . . . . . . 69
Baojun Li, Xiaohong Zheng, and Suichang Sun
12. Investigations on Xeriphytic Festuca spp. from Morocco and Their Associated Endophytes .................................................. 73
M. L. Marlatt, C. P. West, M. E. McConnell, D. A. Sieper, G. W. Buck, 1. C. Correll, and S. Saidi
13. Occurrence ofEndophytes in European Cuitivars, Seed Lots, and Ecotypes of Festuca Species. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
M. Pfannm6ller, St. Eggestein, and W. Sch6berlein
14. Occurrence of Fungal Endophytes in Forage Grasses of South India T. S. Suryanarayanan and K. Rajagopal
15. In Planta Metabolic State of Neotyphodium Endophyte Mycelium Assessed through Use of the GUS Reporter Gene in Combination with Hyphal
81
Enumeration ................................................. 85 Y. Y. Tan, M. Spiering, M. 1. Christensen, K. Saunders, and 1. Schmid
16. Endophytic Fungi in Grasses from Semiarid Grasslands in Spain I. Zabalgogeazcoa, A. Garcia-Ciudad, and B. Garcia-Criado
17. Ecological Diversity in Neotyphodium-Infected Grasses as Influenced by Host
89
and Fungus Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Adrian Leuchtmann
18. Consequences of Endophyte-Infected Grasses on Plant Biodiversity. . . . . . . . . . lO9 Keith Clay
19. Soil Invertebrate Species Diversity and Abundance in Endophyte-Infected Tall Fescue Pastures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
E. C. Bernard, K. D. Gwinn, C. D. Pless, and C. D. Williver
20. Negligible Physiological Responses to Water Deficit in Endophyte-Infected and Uninfected Perennial Ryegrass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
D. 1. Barker, D. E. Hume, and P. E. Quigley
21. Endophyte Effect on Drought Tolerance in Diverse F estuca Species G. W. Buck, C. P. West, and H. W. Elbersen
22. Effects of Endophytic Fungus, Nitrogen, and Plant Damage on Performance of
141
Fall Armyworm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 T. L. Bultman and N. 1. Conard
23. Leaf Blade Colonization by Two Neotyphodium Endophytes, and Ergovaline Distribution within Leaves of Tall Fescue and Meadow Fescue ......... 149
M. 1. Christensen, G. A. Lane, W. R. Simpson, and B. A Tapper
Contents xi
24. Influence of the Ryegrass Endophyte on Phyto-Nematodes ................. 153 l P. J Eerens, M. H. P. W. Visker, R. J. Lucas, H. S. Easton, and
J. G. H. White
25. Influence of the Ryegrass Endophyte on Pasture Production and Composition in a Cool-Moist Environment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
J. P. l Eerens, H. S. Easton, R. l Lucas, J. G. H. White, and K. B. Miller
26. Endophyte Effects on Growth and Water Relations of Tall Fescue. . . . . . . . . . . . 161 H. W. Elbersen and C. P. West
27. Neotyphodium in Native Populations of Arizona Fescue: A Nonmutualis? 165 S. H. Faeth, D. Wilson, M. Helander, K. Saikkonen, F. Schulthess, and
T. l Sullivan
28. Neotyphodium coenophialum Mycelial Protein and Herbage Mass Effects on Ergot Alkaloid Concentration in Tall Fescue ........................ 167
E. E. Hiatt III and N. S. Hill
29. Influence of Neotyphodium Infection on Plant Survival of Diseased Tall Fescue and Ryegrass ................................................. 171
D. E. Hume, P. E. Quigley, and R. Aldaoud
30. Feeding Preferences of Larval Fall Armyworm on Neotyphodium-Infected Grasses: Influence of Host Species and Endophyte Strain. . . . . . . . . . . . . . 175
R. S. Jones, O. l-P. Ball, K. D. Gwinn, and T. A. Coudron
31. Effect of Growth Conditions on Alkaloid Concentrations in Perennial Ryegrass Naturally Infected with Endophyte. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
G. A. Lane, B. A. Tapper, E. Davies, D. E. Hume, G. C. M. Latch, D. l Barker, H. S. Easton, and M. P. Rolston
32. Involvement of Neotyphodium coenophialum in Phosphorus Uptake by Tall Fescue (Festuca arundinacea Schreb.) ...... " . . .. . . . . . . . . . . . . . . . . . 183
D. P. Malinowski, D. P. Belesky, V. C. Baligar, and J. M. Fedders
33. Effects of Natural and Artificial Herbivory on Endophyte-Infected Tall Fescue, F estuca arundinacea and Response by the Aphid, Rhopalosiphum padi 187
l C. Murphy and T. L. Bultman
34. Tiller Mortality in Mixtures of Endophyte-Free Ryegrass and Ryegrass Infected with Two Different Endophytes .................................. 191
A. l Popay
35. The Effects of Neotyphodium-Infected Perennial Ryegrass on the Abundance of Invertebrate Predators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . 195
R. A. Prestidge and S. L. Marshall
36. Photosynthesis and Chlorophyll Fluorescence in Tall Fescue J. H. Reynolds, C. L. Walker, and C. L. Sams
199
xii Contents
37. Investigation of Interactions between Acremonium uncinatum in F estuca pratensis and Various Nematode Species in the Soil .................. 201
W. SchOberiein, St. Eggestein, M. Pfannmoller, and M. Szabova
38. Seasonal Incidence ofChloropid Flies in Tall Fescue J. T. Vogt, C. D. Pless, and K. D. Gwinn
39. The Evaluation and Use of Endophytes for Pasture Improvement Lester R. Fletcher and H. Sydney Easton
40. Use of Natural and Transformed Endophytes for TurfImprovement C. Reed Funk and James F. White, Jr.
205
209
229
41. Magnetic Resonance Imaging of Tall Fescue. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 241 C. L. Anderson, J. P. Dyke, J. F. Green, K. D. Gwinn, and G. W. Kabalka
42. Com Flea Beetle (Chaetocnema pulicaria) Responses to Natural Endophytes of Tall Fescue, Meadow Fescue, and Perennial Ryegrass ................ 243
O. J.-P. Ball, C. Pless, and K. D. Gwinn
43. Immunological Detection of the Neotyphodium-like Endophyte of Annual Ryegrass .................................................... 247
J. D. Carter, O. J.-P. Ball, K. D. Gwinn, and H. A. Fribourg
44. Field Performance of Tall Fescue with Low Infection with Neotyphodium Endophyte ................................................... 251
H. S. Easton and B. M. Cooper
45. Solid State NMR Spectra of Tall Fescue Seed. . . . . . . . . . . . . . . . . . . . . . . . . . .. 255 J. F. Green, K. D. Gwinn, G. W. Kabalka, and C. L. Anderson
46. Neotyphodium coenophialum Mycelial Protein and Herbage Mass Effects on Ergot Alkaloid Concentration in Tall Fescue ........................ 257
E. E. Hiatt III and N. S. Hill
47. Monoclonal Antibody Immunoblot Procedure for Detecting Neotyphodium coenophialum in Seedling Tall Fescue. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 261
E. E. Hiatt III, N. S. Hill, and J. H. Bouton
48. Tissue Immunoblot Procedure for Detection of Neotyphodium coenophialum in Tall Fescue: Optimization of Time Requirements .................... 265
E. E. Hiatt III, N. S. Hill, and J. H. Bouton
49. Ergosterol as an Indicator of Endophyte Biomass in Grass Tissue S. Logendra and M. D. Richardson
50. Analysis of Ergot Alkaloids in Plants and Seeds of Endophyte-Infected Tall
267
Fescue by Gradient HPLC ...................................... 271 R. A. Shelby and M. Flieger
Contents xiii
51. An Appraisal of the Use of Axillary Buds of Grasses as Clonal Material for Inoculation with Neotyphodium Endophytes ........................ 275
W. R. Simpson, M. J. Christensen, and D. E. Hume
52. Observations on Maintaining Endophyte during Backcrossing of Endophyte from Perennial Ryegrass to Annual Ryegrasses ...................... 279
Alan V. Stewart
53. Seed Transmission of an Exotic Endophyte in Tall Fescue S. M. Wilson and H. S. Easton
281
54. Alkaloids of Turf-Type Fine Fescue (Festuca sp.) . . . . . . . . . . . . . . . . . . . . . . . .. 285 Q. Vue, S. Logendra, A. Freehoff, and M. D. Richardson
55. Fescue Toxicosis in Horses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289 Dee L. Cross
56. Physiological Manifestations of Endophyte Toxicosis in Ruminant and Laboratory Species ............................................ 311
Jack W. Oliver
57. Neotyphodium Toxicoses: An Animal Cellular/Molecular Research Technique Perspective .................................................. 347
Brian Larson
58. Cellular and Molecular Techniques for Characterising NeotyphodiumlGrass Interactions .................................................. 361
Ian Garthwaite
59. Significance of Endophyte Toxicosis and Current Practices in Dealing with the Problem in Europe ............................................ 377
G. C. Lewis
60. Significance of Endophyte Toxicosis and Current Practices in Dealing with the Problem in South America ...................................... 383
J. De Battista, N. Altier, D. R. Galdames, and M. Dall' Agnol
61. Significance of Endophyte Toxicoses and Current Practices in Dealing with the Problem in Australia and New Zealand ............................ 389
Janet Z. Foot
62. Significance of Endophyte Toxicosis and Current Practices in Dealing with the Problem in the United States. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
D. M. Ball
63. Immunosuppression in Cattle with Fescue Toxicosis ...................... 411 D. L. Dawe, J. A. Stuedemann, N. S. Hill, and F. N. Thompson
64. Influence of the Ryegrass Endophyte on Sheep Production in a Cool-Moist Environment ................................................. 413
J. P. 1. Eerens, H. S. Easton, R. J. Lucas, J. G. H. White, and K. B. Miller
xiv Contents
65. Endophyte (Neotyphodium lolii) Effect on Parturition Date in Sheep. . . . . . . . .. 417 J. P. 1. Eerens, K. B. Miller, H. S. Easton, R. 1. Lucas, and 1. G. H. White
66. Effects of Endophyte-Infected Fescue Seed Based Diets upon Rabbits Vaccinated against Ergot Alkaloids ............................... 421
N. M. Filipov, F. N. Thompson, N. S. Hill, D. L. Dawe, 1. A. Stuedemann, and 1. C. Price
67. Effect of Ambient and Black-Globe Temperature on Plasma Prolactin Levels in Ewes Grazing Endophyte-Free and Endophyte Infected Ryegrass ....... 425
L. R. Fletcher, B. L. Sutherland, and C. G. Fletcher
68. Ovis Aries: A Model for Studying the Effects of Fescue Toxins on Animal Performance in a Heat-Stress Environment ......................... 429
M. S. Gadberry, T. M. Denard, D. E. Spiers, and E. L. Piper
69. Occurrence of Extreme Alkaloid Levels in Endophyte-Infected Perennial Ryegrass, Tall Fescue, and Meadow Fescue. . . . . . . . . . . . . . . . . . . . . . . .. 433
G. A. Lane, B. A. Tapper, E. Davies, M. 1. Christensen, and G. C. M. Latch
70. Effect of Feeding Ergovaline and Ergine on Growing Rats . . . . . . . . . . . . . . . . .. 437 E. L. Piper, M. S. Gadberry, and T. M. Denard, Z. Johnson, and M. Flieger
71. Determination of Sensitivity to Endophyte-Infected Tall Fescue for Beef Heifers in a Summer Field Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 439
D. E. Spiers, J. E. Williams, B. L. Synder,1. E . Scholljegerdes, and G. E. Rottinghaus
72. Effects of Ryegrass Endophyte and Different White Clover Levels in Pasture on Milk Production from Dairy Cows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 441
E. R. Thorn, D. A. Clark, C. D. Waugh, R. J. McCabe, V. T. van Vught, and B. J. L. Koch
73. Perennial Ryegrass (Lotium perenne) Staggers in the Central Tablelands, NSW, Australia: A Survey of Livestock Producers. . . . . . . . . . . . . . . . . . . . . . . .. 445
W. M. Wheatley
Index 449
INTRODUCTION
Welcome and a Bit of Endophyte History
C. S. Hoveland
Crop and Soil Sciences Department University of Georgia Athens, Georgia
It is a pleasure to welcome each one of you to this third international endophyte symposium, covering a scientific topic that held no interest just 20 years ago. Starting from a remarkable discovery made in Athens, GA, USA, it stimulated other scientists to expand our basic knowledge about endophytes and make applications to plant and animal sciences. Many of you have participated in the exciting happenings in endophyte science which continue to occur. As one of the "senior citizens" at this symposium, I have been privileged to be a small part of this period and would like to share with you a bit of endophyte history.
The early report by Neill (1941) in New Zealand on endophytes in LaTium and Festuca elicited little interest. Another report by Wernham (1942) on the death of Epichlae typhina in tall fescue during storage also did not attract the attention of forage and turf scientists, many of whom were attending to more important duties during a world war. The major factor responsible for eventually stumbling on the importance of endophytes in the USA was the explosive planting of tall fescue in the humid eastern and southern part of the country during the late 1940s and 1950s. Tall fescue succeeded in high stress environments where other cool season perennial grasses were not well adapted. Tall fescue furnished grazing over much of the year and also made an acceptable turfgrass. Its pest and stress tolerances were appreciated but with greater usage for pasture and hay, it earned a reputation for poor animal performance even though crude protein and digestibility values were quite acceptable. This stimulated a great deal of research on chemical components that might be responsible, none of which solved any problems but brought scientists together for discussions. Dr. Joe D. Robbins, a scientist at the USDA Russell Research Center in Athens, GA was at a Fescue Toxicity Conference held in May 1973 at Lexington, Kentucky. He explained, "I became convinced that fescue toxicity involved a fungus of the Clavicipitaceae family" (Robbins, 1983).
Back in Athens, Robbins discussed with fellow scientists Dr. J.K. Porter and Dr. C.W. Bacon the similarity of fescue toxicity in cattle to ergotism and the possibility of a Claviceps related fungus endophytes in the grass. In June of 1973, he visited a farm near
xv
xvi c. S. Hoveland
Mansfield, GA where one group of 40 cows grazing tall fescue showed typical tall fescue toxicity symptoms while another group on another tall fescue pasture had no obvious symptoms. After a number of failures over three years, in 1976 Epichloe typhina was identified and tentatively associated with the fescue toxicity syndrome (Bacon et aI., 1977). The significance of Dr. Robbins' early leadership of this small group of scientists into the cause of tall fescue toxicity resulted in the Athens group, along with a fellow USDA scientist, Dr. R. C. Buckner, the tall fescue geneticists located at the University of Kentucky, being awarded the USDA Unit Award for Superior Service in 1984 "for finding a cause of fescue grass toxicity and incorporating those findings in a new variety of fescue having great agri-economic importance."
During the time of the Georgia investigations, I was having problems with a tall fescue grazing study in central Alabama. Beef steers on two paddocks of tall fescue had a 51 % higher average daily gain than on the other paddock over a 3-year period (Hovel and et aI., 1980). Finding it impossible to explain the consistent differences, I was intrigued by the suggestion of
Bacon et al. (1977) that a grass endophyte was associated with the animal symptoms. The low level of endophyte infestation in our paddocks with good animal gains and high endophyte levels in the poorly performing paddock confirmed their hypothesis. A more complete replicated 4-year grazing study with 94% and 5% endophyte levels conclusively showed the endophyte toxicity relationship (Hoveland et aI., 1983).
In spite of strong evidence for the endophyte as the causal agent of fescue toxicosis, there was considerable skepticism among the research community, especially those who had devoted many years in directions that proved to be futile. One distinguished pasture scientist visiting my experimental tall fescue paddocks in Alabama commented, "I have a difficult time believing that a fungus inside the grass plant could cause fescue toxicosis because if the problem is so simple it would have been discovered long ago!" In Alabama, we formed a multidiscipline committee of scientists to develop research on various aspects of fescue toxicosis, physiology, endophyte transmission, producing endophyte-free seed, and also to examine the plant-endophyte relationship of which we knew nothing. We needed funds and assumed that such an exciting topic would attract money. Grant applications were turned down again and again. In desperation, we asked the state cattlemen associations for support and individual producers gave a total of about $27,000. This was obviously not a high priority item at the time.
Interest in endophytes grew and so in March 1983 we hosted the first tall fescue toxicosis workshop, in Atlanta, GA, attracting a large and interested group of scientists, extension specialists, and seed industry personnel. All of the emphasis was on toxic effects of the en-endophyte with no mention of any beneficial effects to the host plant. This deficiency was rectified in a forage and turf grass endophyte workshop at Corvallis, OR in May 1983 where Dr. C.R. Funk discussed insect resistance in turfgrasses. I recall that Dr. Charles Bacon at that time kept insisting that we needed more studies on the endophytehost plant relationship and possible benefits to the plant. His concerns were vindicated later when farmers started planting pastures with seed of a new endophyte-free cultivar, AU Triumph, which we had released. Many farmers used grazing practices similar to that on endophyte-infected tall fescue, grazing closely throughout the hot summer season. The result often was serious stand losses which were related to the intolerance of this endophyte-free, erect-growing cultivar to close grazing in summer. In consequence, planting of endophyte-free tall fescue declined sharply, causing distress to the seed industry. As we found out later, endophyte-free tall fescue pastures could be productive and persistent if grazing practices maintained a stubble of 7 to 8 cm during summer.
Introduction xvii
As USA research and extension workers expanded efforts on endophytes, the annual tall fescue toxicosis workshop grew in size and stature. Concurrently, the exciting report by Fletcher and Harvey (1981) in New Zealand that associated ryegrass staggers with endophyte infection expanded the interest in study of endophytes in that country. Research money was finally being directed to endophyte study in the USA, New Zealand, and in other countries around the world, much of it to very practical experiments but increasingly to more basic studies on the endophyte-host plant relationship and identification of the chemical components responsible for toxicity problems.
Great progress has been made in our basic knowledge of endophytes and their useful application as evidenced by reports at the two preceding international endophyte symposia in the USA and New Zealand. Much of the research effort has been directed toward toxic effects of endophytes on livestock and solutions to the problem. Meantime, scientists have continued to utilize endophytes for improved stress and pest tolerance of turf grasses. This will continue to be important but the use of modified endophytes for improving stress and pest tolerance in forage grasses and other crop plants offers exciting new possibilities. I expect this symposium will continue to build on those of the past and open new avenues of understanding. Again, a warm welcome!
REFERENCES
Bacon, C.w., J.K. Porter, J.D. Robbins, and E.S. Luttrell. 1977. Epichloe typhina from toxic tall fescue grasses. App\. Environ. Microbio\. 34:521-581
Fletcher, L.R., and \.e. Harvey. 1981. An association of a Lolium endophyte with ryegrass staggers. N.Z. Vet. J. 29: 185-186.
Funk, e.R., P.M. Halisky, and R.H. Hurley. 1983. Implications of endophytic fungi in breeding for insect resistance. p. 67-75. Proc. Forage and Turfgrass Endophyte Workshop. May 3--4, 1983, Corvallis, OR. Oregon Agric. Ext. Serv., Corvallis, OR.
Hoveland, C.S., R.L. Haaland, C.C. King, Jr., W.B. Anthony, E.M Clark, J.A. McGuire, L.A. Smith, H.W. Grimes, and J.L. Holliman. 1980. Association of Epichloe typhina fungus and steer performance on tall fescue pasture. Agron. J. 72:1064-1065.
Hoveland, C.S., S.P. Schmidt, C.C. King, Jr., J.W. Odom, E.M. Clark, J.A Smith, H.W. Grimes, and J.L. Holliman. 1983. Steer performance and Acremonium coenophialum fungal endophyte on tall fescue pasture. Agron. J. 75:821--824.
Neill, J.C. 1941. The endophytes of Lolium and Festuca. N.Z. J. Sci. Techno\. 23:185-193. Robbins, J.D. 1983. The tall fescue toxicosis problem. p. 1--4. Proc. Tall Fescue Toxicosis Workshop. March
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