Tomato Diseases: Identification, Biology and Control: A Colour Handbook PDF

INTRODUCTION

To identify a disease in the field, the practitioner must have academic training and extensive knowledge of various disciplines together with experience. One must remember that in Greek, diagnôsis means ‘knowledge'. The extent of this knowledge is justified by the large number and diversity of the causes of diseases. Thus a good practitioner needs to be informed of all symptoms and signs caused by disease. But his expertise is not only related to the biology of pathogens (sources of contamination, modes of transmission, favourable weather) but also to understand the exact nature of the pathological context. The latter may be insufficient or inadequate, particularly in the context of a nonparasitic disease. Thanks to many observations and appropriate questions, he/she will also be able to define the environmental and cultural conditions of the disease development. In fact, the diagnostician is a real detective, using a procedure constructed from his knowledge and especially his experience of diagnosis. It consists of a progressive sequences of observations of the diseased plants and their different organs, of questions mainly intended to clarify the cultural context, and identifying possible hypothetical causes and prioritizing them.

This book attempts to formalize this most difficult art that represents the diagnosis of plant diseases. We learned and perfected the particular approach outlined in our previous works on diseases of tomato, cucurbits, tobacco, and salads. This included a knowledge and the intellectual processes being used by an experienced generalist phytopathologist and is now used when confronted with the identification of tomato diseases.

The objectives of this book are therefore many:

– Allow readers to identify interactively parasitic and nonparasitic diseases of tomato common in the world from both descriptions and photos, thus avoiding the many possible causes of confusion in diagnosis.

– Make available a summary of recent knowledge on almost all of common and serious pests and pathogens on tomato.

– Help them choose, knowingly, the methods of protection most relevant to control these pests;

– Contribute to their development in the diagnosis of tomato diseases to improve their level of expertise.

The section Diagnosing parasitic and nonparasitic diseases is designed as a true diagnostic tool, illustrated by more than 900 colour photographs and numerous illustrations to aid the observation of the plants. This tool can easily be used as the symptoms are grouped under simple headings. It is also educational and should ultimately enable the reader gradually to acquire the approach and the many factors needed to establish a reliable diagnosis.

We draw the attention of prospective readers to the benefits of using this method, taking into account the methodology defined in the following pages. Indeed, some readers with knowledge may tend to ‘bypass' the proposed process. In this case, they may be confused by the organisation of the work which is not typically designed according to the nature of the diseases, but rather takes into account the symptoms that characterize them.

Once identification is complete, the reader will find a detailed description for the majority of pests and pathogens in the third section, Principal characteristics of pathogenic agents and methods of control. This section details the distribution and impact on tomato growing in the world, the main symptoms produced, and their morphological and biological characteristics. With this knowledge, readers will be able to choose the best suited control method and to define a protection strategy to be implemented immediately or during the next crop.

The first and third sections are designed to raise awareness of the tomato plant and its botanical family and its cultivation, but especially the potential offered by the Solanaceae in term of resistance to diseases.