/ VIRUS DISEASES AND NONINFECTIOUS DISORDERS OF STONE FRUITS IN NORTH AMERICA Agriculture Handbook No. 437 Agricultural Research Service UNITED STATES DEPARTMENT OF AGRICULTURE VIRUS DISEASES AND NONINFECTIOUS DISORDERS OF STONE FRUITS IN NORTH AMERICA Agriculture Handbook No. 437 This handbook supersedes Agriculture Handbook 10, Virus Diseases and Other Disorders with Viruslike Symptoms of Stone Fruits in North America. Agricultural Research Service UNITED STATES DEPARTMENT OF AGRICULTURE Washington, D.C. ISSUED JANUARY 1976 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C 20402 — Price $7.10 (Paper Cover) Stock Number 0100-02691 FOREWORD The study of fruit tree virus diseases is a tedious process because of the time needed to produce experimental woody plants and, often, the long interval from inoculation until the development of diagnostic symptoms. The need for cooperation and interchange of information among investigators of these diseases has been apparent for a long time. As early as 1941, a conference was called by Director V. R. Gardner at Michigan State University to discuss the problem. One result of this early conference was the selection of a committee (E. M. Hildebrand, G. H. Berkeley, and D. Cation) to collect and classify both published and unpublished data on the nomenclature, symptoms, host range, geographical distribution, and other pertinent information on stone fruit virus diseases. This information was used to prepare a "Handbook of Stone Fruit Virus Diseases in North America," which was published in 1942 as a mis- cellaneous publication of the Michigan Agricultural Experiment Station. At a second conference of stone fruit virus disease workers held in Cleveland, Ohio, in 1944 under the chairmanship of Director Gardner, a Publication Committee (D. Cation, G. H. Berkeley, L. C. Cochran, F. P. CuUinan, and R. J. Haskell was appointed to revise the text of the first handbook. This revision resulted in the publication in 1951 of Agriculture Handbook 10, "Virus Diseases and Other Disorders with Viruslike Symptoms of Stone Fruits in North America." The work of this committee was helped greatly by the passage of the Research and Marketing Act of 1946 and the subsequent establishment and funding of regional research projects to investigate stone fruit virus diseases. Research and Marketing Act funds were used to publish Handbook 10. State workers in the several regions cooperated through an informal Inter- regional Research Committee that functioned actively, and helped to establish the formal IR-2 Committee and project. The regional projects, with the active cooperation of the United States Department of Agriculture and the Canadian Department of Agriculture, have reduced duplication of research efforts and improved dissemination of information to the public. The formation of the European Committee for Cooperation in Fruit Tree Virus Research has aided the cooperative effort in North America through exchanges of information and personnel and has helped to establish international standards for the detection and control of fruit tree virus diseases. Since the publication of Handbook 10, several pathologists, who were promi- nent authors in that book, have retired from active teaching or research. Because so much of our present knowledge about stone fruit virus diseases was obtained from their pioneering efforts, we wish to acknowledge their influence on this discipline and acknowledge our debt to the guidance they provided in the original edition from which we have drawn freely in this new handbook. We particularly want to thank G. H. Berkeley (deceased), E. M. Hildebrand, Lee III M. Hutchins, G. W. Keitt (deceased), T. B. Lott, John A. Milbrath, D. H. Palmiter (deceased), T. E. Rawlins (deceased), E. L. Reeves, B. L. Richards, and R. S. Willison. Illustrations in this book were taken from Agriculture Handbook 10, "Virus Diseases and Other Disorders With Viruslike Symptoms of Stone Fruits in North America," or were submitted by the authors of the various sections. Credit is gratefully extended to the following contributors of illustrations for sections of which they are not authors: American Potash Institute, figure 152; Neis R. Benson, figures 145, 146, and 147; and A. E. Hitchcock, figures 142, 143, and 144. This handbook is the result of the cooperative effort of the authors, who represent all the fruit-growing regions of North America. The Editorial and Publication Committee is deeply indebted to them for their willingness to par- ticipate in the preparation of this revision. Special credit is due L. C. Cochran, retired, former chief. Fruit and Nut Crops Research Branch, Plant Science Research Division, ARS, for his help in initiating the production of this book. We want to recognize J. R. McGrew, plant pathologist, USD A, for his technical advice and review of the manuscript and his efforts in collecting of the illus- trations. R. M. Gilmer J. Duain Moore George Nyland M. F. Welsh T. S. Pine, chairman, Editorial and Publication Committee [Thomas Sheffield Pine, who served as chairman of the Editorial and Publi- cation Committee for this book, died April 2, 1970, after an illness of several months. The other members of the Editorial and Publication Committee wish to give special recognition to his dedication, organizational ability, and hard work in assembling the manuscripts, unifying and verifying literature citations, and mounting the illustrations. He completed the work on schedule under extremely difficult conditions and failing health.} IV CONTENTS Page Introduction VIII Techniques of Investigating Stone Fruit Viruses 1 Control of Stone Fruit Virus Diseases 10 IR-2, The Interregional Deciduous Tree Fruit Repository 16 Quarantine and the Detection of Stone Fruit Viruses in Plant Importations 23 Virus Diseases of Almond and Apricot 33 Almond virus bud failure 33 Apricot pucker leaf 43 Apricot ring pox 45 Virus Diseases of Peach 50 Asteroid spot 50 Peach blotch 56 Peach calico 58 Peach mosaic 61 Peach mottle 71 Peach rosette 73 Peach stem pitting 77 Peach wart 88 Peach yellows 91 Phony 96 Prunus ring spot group 104 Red suture 133 Rosette mosaic 135 Stubby twig 139 Weak peach 144 X-disease 145 Yellow bud mosaic 156 Virus Diseases of Plum and Prune 166 Plum line pattern 166 Prune diamond canker 176 Prune dwarf 179 Virus Diseases of Sour Cherry 191 Bark splitting in Montmorency cherry 191 Green ring mottle 193 Pink fruit 200 Virus gummosis of Montmorency 202 V Page Virus Diseases of Sweet Cherry 204 Albino 204 Apple chlorotic leaf spot and other filamentous virus infections in Prunus 206 Black canker 209 Blossom anomaly of cherry 211 Cherry boron rosette 213 Cherry mottle leaf 216 Cherry rasp leaf 219 Cherry twisted leaf 222 Freckle fruit 226 Fruit pitting of sweet cherry 227 Little cherry 231 Cucumber mosaic virus infection in Prunus 238 Rough bark of sweet cherry 240 Rusty mottle group 242 Short stem 250 Spur cherry 252 Sweet cherry rough fruit 254 Tobacco mosaic virus infection m Prunus 256 Xylem aberration 257 Nontransmissible Disorders That Resemble Virus Diseases 259 Almond corky spot 259 Apricot gumboil 261 Chlorotic fleck of myrobalan plum 265 Constriction disease of Stanley prune 268 High temperature mottle of Montmorency cherry 272 Italian Prune leaf spot 274 Italian Prune sparse leaf 277 Noninfectious bud failure in almond 278 Noninfectious plum crinkle leaf 283 Noninfectious plum shot hole 285 Peach false wart 288 Peach variegation 290 Peach yellow spot 292 Plum rusty blotch 294 Prune crinkle leaf 297 VI Page Prune leaf casting mottle 299 Pustular canker of Tragedy prune 302 Standard prune constricting mosaic 304 Sweet cherry crinkle leaf, deep suture, and variegation 306 Diagnosis of Stone Fruit Virus Diseases and Certain Disorders That Resemble Virus Diseases 314 Nutritional Disorders That Resemble Virus Diseases 316 Herbicide Injuries That Resemble Virus Diseases 347 Air Pollution Injuries That Resemble Virus Diseases 355 Literature Cited 365 Appendix 405 Common and Scientific Names of Plants mentioned in the Text 405 Contributors 408 References to Stone Fruit Virus Diseases Published After Closing Date for Receipt of Manuscripts 411 Host-Disease Index 424 Trade names are used in this publication solely for the purpose of providing specific information. Mention of a trade name does not con- stitute a guarantee or warranty of the product by the U.S. Department of Agriculture or an endorsement by the Department over other products not mentioned. In citing this handbook, the Editorial and Publication Committee would be pleased if authors would refer directly to particular authors and sections, for example— NYLAND, GEORGE. 1974. ALMOND VIRUS BUD FAILURE. In Virus Diseascs and Noninfectious Disorders of Stone Fruits in North America. U.S. Dept. Agr., Agr. Handbook 437. VII INTRODUCTION Much new information has been obtained about stone fruit viruses and the diseases they incite since the publication of Agriculture Handbook 10 in 1951. The purpose of this new publication is to provide professional investigators and students with an updated reference work and agricultural technicians and orchardists with an illustrated handbook to help in diagnosing virus diseases in the field. Therefore, this book contains sections on the basic and applied approaches to research on stone fruit virus diseases as well as extensive descrip- tive material on the symptoms, distribution, control, and economic factors pertaining to these diseases. Progress in our knowledge