Rhizosphaera Needle Cast of Spruce

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Rhizosphaera needle cast, caused by the fungus Rhizosphaera kalkhoffii, is one of the most common diseases spruce in the urban landscape. The predominance of this disease is due to the popularity of Colorado blue spruce (Picea pungens), the number one conifer throughout most of the United State. Disease severity (to Rhizosphaera, and other disease), and resulting loss of aesthetics shortens the life span of most Colorado Blue Spruce to an average age of 30 in the urban landscape. Occasionally, young trees are killed by the pathogen, but more commonly branches lose their needles resulting in misshapen trees that attract Ips beetles, forcing homeowners to ultimately prune at ground level.

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