After introducing the history and significance of plant pathology (Chapter 1), the author discusses how pathogens reach and infect their hosts' tissue (Chapter 2), attack their hosts (enzymes, toxins, growth regulators) (Chapter 3), and which physiological processes pathogens are most likely to affect in their hosts (translocation, photosynthesis) (Chapter 4).
This is followed by a discussion of how plants defend themselves against pathogens (preexisting and induced structural and chemical responses) (Chapter 5). The sixth chapter introduces the genetics of host-pathogen interactions, an area that is developing quickly since the localization and sequencing of the first resistance gene and has been revised accordingly. Environmental conditions strongly influence the expression and development of plant disease (Chapter 7), while factors such as disease resistance, pathogen virulence will affect disease epidemiology and predictions on how a pathogen's population size will increase through time and affect yield loss (Chapter 8). Mechanical, biological and chemical methods of disease control are presented in Chapter 9.
The second section of the book describes which environmental factors and groups of organisms can cause given diseases. For each group of organisms (fungi, prokaryotes (bacteria and mollicutes), viruses, nematodes, parasitic plants and flagellate protozoa), the author first describes the taxonomy of the group and discusses the general characteristics of a group (ecology, identification, isolation, life cycle) before presenting given pathogens within each group. For example, within the fungi, under oomycetes, Phytium and Phytophthora (causing downy mildew ) and Albugo (white rust of crucifers) are discussed. Under each organism, one will typically find a general introduction to the disease, followed by the symptoms, description of the pathogen and its life cycle, a discussion of the development of the disease and specific methods of control.
The major changes between the third and fourth editions, besides the genetics section, include a revision of the taxonomy of fungi, and a revised taxonomy of viruses. For the fungi, the slime molds are now grouped under the kingdom protozoa rather than fungi, and the oomycetes belong to the kingdom chromista. The viruses are now classified according to their molecular material (DNA or RNA, single- or double-stranded), and shape among other characteristics. We now have families and genera for viruses. In the third edition, viruses were categorized under the plant they affected, virus diseases of tobacco, tomato, or potato for example. This is a major revision which deserves attention.
For all biologists interested in the study of plant pathogens, this book is a great reference and a general introduction to the discipline. It is a great textbook for graduate courses, but some may prefer a less detailed textbook for their undergraduates. Plant Pathology by George Agrios covers what is typically part of a plant pathology class and does a nice job of it. However, this does not include studies of natural plant populations. If you are looking for information on the impact of disease on reproduction and survival of individual plants, on population structure and on how disease maintains genetic diversity in the host population, you will be disappointed. This book does not cover ecology and population biology. This subject area has been covered previously by Jeremy Burdon (1987) in his book entitled 'Diseases and plant population biology' (Cambridge University Press) and, in 'Plant resistance to herbivores and pathogens' by R. S. Fritz and E.L. Simms (1992, The University of Chicago Press). - Johanne Brunet, Oregon State University, Corvallis, Oregon