\ Advances in Soil-borne Plant Diseases "This page is Intentionally Left Blank" Advances in Soil-borne Plant Diseases Rob Jenkins C.K. Jain Oxford Book Company Jaipur, India ISBN: 978-93-80179-15-5 Edition 2010 Oxford Book Company 267, lO-B-Scheme, Opp. Narayan Niwas, Gopalpura By Pass Road, Jaipur-302018 Phone:OI41-2594705,Fax:OI41-2597527 e-mail:
[email protected] website: www.oxfordbookcompany.com © Reserved Typeset by: Shivangi Computers 267, IO-B-Scheme, Opp. Narayan Niwas, Gopalpura By Pass Road, Jaipur-302018 Printed at: Mehra Offset Press, Delhi All Rights are Reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, without the prior written permission of the copyright owner. Responsibility for the facts stated, opinions expressed, conclusions reached and plagiarism, if any, in this volume is entirely that of the Author, according to whom the matter encompassed in this book has been originally created/edited and resemblance with any such publication may be incidental. The Publisher bears no responsibility for them, whatsoever. Preface Plant diseases result when a susceptible host and a disease-causing pathogen meet in a favourable environment. If anyone of these three conditions were not met, there would be no disease. Diseases may occur in natural environments, but they rarely run rampant and cause major problems. In contrast, the threat of disease epidemics in crop production is constant. The reasons for this are becoming increasingly evident. Soilborne diseases result from a reduction of biodiversity of soil organisms. Restoring beneficial organisms that attack, repel, or otherwise antagonise disease-causing pathogens will render a soil disease-suppressive. Plants growing in disease-suppressive soil resist diseases much better than in soils low in biological diversity. Beneficial organisms can be added directly, or the soil environment can be made more favourable for them through use of compost and other organic amendments. Compost quality determines its effectiveness at suppressing soil-borne plant diseases. There are two types of disease suppression: specific and general. Specific suppression results from one organism directly suppressing a known pathogen. These are cases where a biological control agent is introduced into the soil for the specific purpose of reducing disease incidence. General suppression is the result of a high biodiversity of microbial populations that creates conditions unfavourable for plant disease development. Soil pH, calcium level, nitrogen form, and the availability of nutrients can all play major roles in disease management. Adequate crop nutrition makes plants more tolerant of or resistant to disease. Also, the nutrient status of the soil and the use of particular fertilisers and amendments can have significant impacts on the pathogen'S environment. This book describes the characteristics of various soil-borne diseases of plants and the measures to prevent them. It provides a detailed description of the life of the pathogens, chemical and pesticidal means of regulation, taxonomic changes have been made in bacteria, fungi, nematodes and viruses; changing patterns of diseases and many recently reported diseases. This book should be useful to gardeners, landscape architects, florists, nurserymen, seed and fungicide dealers, pesticide applicators, cooperative extension agents and plant pathologists. It should also be a useful reference book for plant pathology classrooms and in some cases used as a textbook. I