In the 1840s, a fungus-like organism called Phytophthora infestans destroyed Ireland's potato crop, leading to the Irish Potato Famine. Since then, approximately 100 Phytophthora species have been identified, many of which are pathogens of important plant crops. Many novel species have been reported in recent years in both the USA and Europe, mainly due to increased forest and nursery surveys to search for P. ramorum, the cause of sudden oak death. The discovery of many new species from these targeted surveys is indicative of our limited understanding of the diversity of Phytophthora in nature and suggests that many species remain to be discovered. Systematically cataloging the key genotypic and phenotypic traits of the known species is essential for future surveys and disease management. This catalogue provides a baseline for accurate identification and risk assessment of newly isolated Phytophthora strains by allowing them to be compared to the genetic and phenotypic data on known species.

This book offers an easy-to-follow guide for identifying Phytophthora species based on morphological keys and DNA fingerprints. Procedures for generating both types of data are provided. The book is an excellent laboratory reference for students studying plant pathology/mycology and plant disease diagnosticians. However, as noted by the authors, this book is a work in progress and currently covers only ~60 species. The DNA fingerprint key described in this book for species identification is handy for those who need to quickly determine the species identity of a large number of Phytophthora isolates. However, this key will become more difficult to use as the number of described species increases. The number of references for each of the species described in the book is very limited. Despite such limitations, in combination with other published references (e.g. Phytophthora Disease Worldwide by Erwin and Ribeiro, APS Press) and online resources (e.g. Phytophthora Database; www.phytophthoradb.org/), this book will certainly contribute to global efforts to deal with this group of 'plant destroyers'.