Westcott’s Plant Disease Handbook Westcott’s Plant Disease Handbook Seventh Edition Revised by R Kenneth Horst With 90 figures and tables 13 Professor R Kenneth Horst Department of Plant Pathology Plant Science 319 Cornell University Ithaca, NY 14853 USA Library of Congress Control Number: 2008922117 ISBN: 978-1-4020-4585-1 Springer Dordrecht, Berlin, Heidelberg, New York This publication is available also as: Print publication under 978-1-4020-4584-4 and Print and electronic bundle under ISBN 978-1-4020-5193-7 This work is subject to copyright All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in other ways, and storage in data banks Duplication of this publication or parts thereof is only permitted under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag Violations are liable for prosecution under the German Copyright Law © Springer-Verlag Berlin Heidelberg New York 2008 The use of registered names, trademarks, etc in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use Springer is part of Springer Science+Business Media springer.com Editor: Zuzana Bernhart, Dordrecht / Sandra Fabiani, Heidelberg Development Editor: Sylvia Blago, Heidelberg/Lydia Müller, Heidelberg Typesetting and Production: le-tex publishing services oHG, Leipzig Cover Design: deblik, Berlin Printed on acid-free paper SPIN: 11614579 2109 – This 7th Edition of the Plant Disease handbook is dedicated to the mentoring experiences I have had the pleasure of experiencing starting with Pleasant View Grade School, North Lawrence, OH, to Massillon Washington High School, Massillon, OH, to Ohio University, Athens, OH, to The Ohio State University, Columbus, OH, to Yoder Bros., Inc., Barberton, OH, to Cornell University, Ithaca, NY (Professor, Department of Plant Pathology) Although I felt in those early years that I was doing all the learning, I soon found that mentoring was a two-way phenomenon Not only was I mentoring my students at Cornell University, but I found I was learning from them as well I was stimulated to reflect on this by my two youngest grandchildren, Madeline Turner and Trevor Horst to whom I dedicate this 7th Edition as well as the students who taught me while I was teaching them Madeline initiated this process when I asked her what she was learning in kindergarten When she listed all that she was learning I indicated she was really getting smart and that maybe Grampy should go to kindergarten so that he could get smart She said “No Grampy you can’t” and I asked her “why not” and she aid “Because you’re no kid anymore” What a great answer and also very profound since she was really telling me I needed to continue moving beyond being a kid in my learning process Students (Masters, Doctoral and Post-Doctoral Students) I have mentored and from whom I have also learned much Jamil Abu-Sadah Richard Biamonte Lester Burgess Eugene Oscar Erickson Donna Gardiner-Matteoni Mary Handley Jeffrey R Houge Hussein Ali Ahmed Hussein Catherine M Klein Selin Kryzcynski Randolph Edward McCoy Robert J McGovern Elzbieta Paduch-Cichal Cristi Lynn Palmer Hugh Allen Poole Leah LeEarle Porter Ramona Ann Reiser Charles Peter Romaine Nancy Jane Schenk Margosheta Schollenberger Gail Lynn Schumann Ann Finer Silverglate Robert W Stack Marek Szyndel Arnold T Tschanz Sek-Man Wong Preface to the Seventh Edition 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 responsibility for the fourth edition, the fifth edition, the sixth edition, and now the seventh edition was not taken lightly The task has been a formidable one I have always had great respect professionally for Dr Cynthia Westcott That respect has grown considerably with the completion of the four 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 In the years since the sixth edition there were more than 600 new reports of diseases on plants 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 ” Dr Cynthia Westcott passed away March 22, 1983 This revision of the Handbook retains the same general format contained in the previous editions The chemicals and pesticides regulations have been updated; major taxonomic changes have been made in the bacteria, fungi, nematodes and viruses; the changing picture in diseases caused by viruses and/or viruslike agents have been described 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 the Handbook In addition photographs have been retained from the sixth edition as well as the color photograph section For the photography work I am grateful for the help and expertise of Kent E Loeffler I also had access to the Cornell Plant Pathology Herbarium, which contains a wealth of photographic work VIII Preface to the Seventh Edition on plant diseases that has been supplied by numerous scientists over many years This book should be useful to gardeners, master gardeners, botanical gardens, landscape architects, florists, nurserymen, seed and fungicide dealers, pesticide applicators, arborists, cooperative extension agents and specialists, plant pathologists, diagnostic laboratories and consultants The book should also be a useful reference book for plant pathology classrooms and in some cases used as a textbook February 2008 R Kenneth Horst Acknowledgements I am indebted to many people for advice and suggestions for the 7th edition The reviewers acquired by Kluwer Academic Publisher to review the 5th Edition and to advise on significance of a 6th Edition provided many helpful suggestions which were used in the 7th Edition Moreover, a few individuals who were particularly helpful in my tasks of updating and putting together the revision for the 7th Edition into an appropriate format were J Esnard, K Hodge, S J Ingalls, K Loeffler, C Palmer, K Snover, R E Stall, B Szyndel and M S Szyndel Finally, I recognize and appreciate the professional and efficient job of typing the manuscript by Margaret Haus and her dedicated efforts in aiding me in proofreading, which was a major task with the increasing size of the book and the changing scientific names of the pathogenic organisms Plate a, b Rust on Rose caused by Phragmidium mucronatum c Cedar-Apple Rust on Apple caused by Gymnosporangium juniperi-virginianae Plate a Cedar-Apple Rust on Cedar caused by Gymnosporangium juniperi b Stunt on Chrysanthemum caused by Chrysanthemum Stunt Viroid Var Dark Pink Orchid Queen Plate a Green Flowers on Chrysanthemum caused by Aster Yellows Phytoplasma b Phyllody on Hydrangea caused by a Phytoplasma Pathogen Plate a, b Mosaic on Rose caused by Prunus Necrotic Ringspot Virus c Foliar Symptoms on Chrysanthemum (Variety Bonnie Jean) caused by (clockwise from upper left) Chrysanthemum Chlorotic Mottle Viroid, Healthy Leaf, Potato Spindle Tuber Viroid, Chrysanthemum Stunt Viroid, and Potato Spindle Tuber Viroid (Mild Strain) Plate a Bacterial Leaf Rot on Dieffenbachia caused by Erwinia chrysanthemi b Bacterial Leaf Rot on Philodendron caused by Erwinia chrysanthemi Plate a Common Leafspot on Boston Ivy caused by Guignardia bidwellii b Crown Gall on Chrysanthemum caused by Agrobacterium tumefaciens Plate a Ringspot on Tomato Fruit caused by Cucumber Mosaic Virus b, c Powdery Mildew on Rose caused by Podosphaera pannosa Plate a Late Blight on Potato caused by Phytophthora infestans b Powdery Mildew on Begonia caused by Erysiphe cichoracearum c Mosaic on Squash caused by Cucumber Mosaic Virus Plate 10 a Dollar Spot on Turf caused by Sclerotinia homeocarpa b Copper Injury on Rose caused by sprays containing Copper c Blackspot on Rose caused by Diplocarpon rosae Plate 11 Foliar Nematode on Chrysanthemum caused by Aphelenchoides ritzemabosi Plate 12 a Foliar Nematode on Chrysanthemum caused by Aphelenchoides ritzemabosi b Apple Scab on Apple caused by Venturia inaequalis Plate 13 a, b, c, d Rust on Jack-in-the-Pulpit caused by Uromyces caladii Plate 14 a, b Leaf Spot on Dracaena caused by Physalospora dracaenae c Yellow Leaf Blight on Corn caused by Phyllosticta maydis d Blossom Blight on Rose caused by Botrytis cinerea Plate 15 a Flower and Leaf Blight on Geranium caused by Botrytis cinerea b Scab on Citrus caused by Elsinoë fawcettii c Downy Mildew on Rose by Peronospora sparsa Plate 16 a Brown Rot on Cherry caused by Monilinia fructicola b Downy Mildew on Rose by Peronospora sparsa ... are exempt from the relevant protective laws and regulations and therefore free for general use Springer is part of Springer Science+Business Media springer.com Editor: Zuzana Bernhart, Dordrecht... countries For home gardeners it means using certified seed or plants, sorting bulbs before planting, discarding any that are doubtful, possibly treating seeds or tubers or corms before they are planted,... manufacturing plants are to be registered and government-inspected All pesticide products must be registered whether shipped in interstate or intrastate commerce Other provisions are of various degrees