Accompanies a book (Diseases of Herbaceous Perennials) whose aim is to help readers to recognize the major diseases of herbaceous perennials and to manage them effectively. It will be valuable to commercial plant producers and retailers, landscape managers and professional and home gardeners. To assist those new to the concepts of plant disease, supplementary information is included on the different kinds of micro-organisms that can cause contagious plant problems. References are provided for further reading and a glossary is available to help readers understand unfamiliar terms.