Fairy rings. Photo provided by: Clemson University – USDA Cooperative Extension Slide Series, , Bugwood.org

Fairy rings (symptoms) on golf course fairway. Photo provided by: William M. Brown Jr., Bugwood.org

Downy mildew on rose leaves. Photo by: Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org

Downy mildew on rose. Photo provided by: Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org

A new text, “Diseases of Herbaceous Perennials”, has been released by APS Press and is an excellent resource.