Book Review: Compendium of Pea Diseases and Pests, Third Edition

Harveson, R. M., J.S. Pasche, L. Porter, W. Chen, M. Burrows, eds. 2021. Compendium of Pea Diseases and Pests, Third Edition. American Phytopathological Society, St. Paul, MN, USA. Softbound, 8 ½ x 11 inches, 130 pp. $149 (10% discount for APS members).

This compendium is the latest of more than 40 compendia on various food, fiber, and ornamental crops published by the American Phytopathological Society. Originally released in 1984 and revised in 2001, this third edition includes more than 200 color photographs, of which 90% are original to this volume. The information within has been substantially updated and expanded from previous editions. The volume aims to be global in scope and includes information on the distribution of various pests and diseases in geographic areas where they are most significant; authors or editors from seven countries have contributed.

The compendia are aimed at those in applied fields who have a need to identify plant problems, such as extension specialists, agricultural professionals, horticulturists, diagnosticians, and perhaps home gardeners with a serious sense of curiosity.

Excluding the introduction, the volume is divided into three main sections: Infectious Diseases; Insect Pests and Their Natural Enemies; and Noninfectious Disorders, including vertebrate pests. This is followed by a field guide to disease diagnosis based on symptoms and observations, and a glossary of terms. The Introduction, a few pages in length, discusses the cultivation, breeding, and production of pea, and gives a botanical description of Pisum sativum, the subject of the book. Sadly, a drawing of the plant, its floral structures and stages of seedling germination have been removed since the second edition; the authors rely instead on written descriptions of morphology. Part I, the largest, covers 27 diseases caused by, in descending order of abundance, fungi and oomycetes, viruses, nematodes, bacteria, and a phytoplasma. Although not a disease, for the first time a parasitic weed has been included. Each entry in this section follows the same format: introductory material about the disease, often including historical information and geographical distribution; symptoms resulting from infection; causal agent; disease cycle and epidemiology; management; and selected references.

What makes the compendia in this series particularly useful, besides the prolific images, is the inclusion of information about other problems that can affect a crop. Part II includes information on 10 destructive arthropod pests plus background on natural enemies including a page on entomopathogenic fungi. This section also follows a set format for information presentation: general morphological identification of the pest; biology and life cycle; crop damage; monitoring and thresholds; IPM strategies; and selected references. Photographs illustrate the life stage of the insect that is most damaging; some sections show both immature and adult stages. The inclusion of photographs of the damage caused by arthropod pests, while not as prolific as this reviewer would like, is a leap forward. Often those who are trying to determine why seedlings, leaves, or entire plants are disappearing are left with symptoms only – the pest may no longer be present. It would be highly useful if future compendia could document more fully, with images, the damage caused by insects and mites. Inclusion of images of natural enemies is a welcome addition, since field personnel who are uncertain whether these insects need to be controlled often submit them for identification.

Part III discusses abiotic problems, mostly caused by the environment and nutritional problems, which can be most of what effects a crop in some years. These sections are either new or greatly expanded and are also accompanied by helpful photographs.

This volume is well illustrated for most of the problems presented with color images, showing symptoms on different plant structures or at different degrees of severity. Some overall field shots are included, which are useful on a gross scale to show the impact of severe disease. Photographs of symptoms are most successful when the defining characteristics of the disease or problem can clearly be seen and distinguished from the background, which fortunately is true for most of the images included. The photos are, thankfully, slightly larger than they have been in previous editions.

There are a few shortcomings. Description of phytopathogens vary in their completeness; captions for photographs of fungi growing on artificial media may not identify the medium; and scale bars tend to come and go, depending on who contributed the photograph. Photomicrographs of spores are often shown on their own, without conidiophores or other context. Curiously, only morphological or, in the case of the phytobacteria, biochemical information, is given for pathogen identification. The second edition included some molecular methods for specific detection, but these have been stripped from the current edition. Although not all field professionals have access to PCR machines and sequencers, they may not have access to autoclaves, Petri plates, and artificial media either. However, many diagnostic laboratories and personnel associated with universities do have the means to employ molecular methods for detection and identification. Given that some of the pathogens are of regulatory concern and are challenging to identify morphologically (e.g., the “Ascochyta” complex), it would have been useful to have means other than fungal morphology to confirm identity. References could have been specifically cited as an opening to the relevant literature.

The shortcomings of this volume are outweighed by its usefulness. It is a concise and complete assemblage of information on biotic organisms, and some noninfectious problems, that affect pea production. This compendium will appeal to those in applied fields who are not specialists in pea diseases. These compendia are often staples in diagnostic laboratories and often show up in pickup trucks, with sample bags, soil probes and sweep nets.

Melodie Putnam
Director, Oregon State University Plant Clinic
Corvallis, OR
putnamm@oregonstate.edu