Colorado Blue Spruce and Other Conifers Disorder: Rhizosphaera Needle Cast
Author(s) M. F. Heimann, G. R. Stanosz
Rhizosphaera needle cast occurs throughout the state of Wisconsin but infects only certain conifer species. Colorado blue spruce is the most common host, but Engelmann, black, Serbian, and Sitka spruces are also susceptible, as well as Austrian, mugo, and eastern white pine, Douglas fir, and western hemlock. This fact sheet describes the disorder's life cycle and symptoms as well as offering means of effective control (2 pages).