Rhizosphaera Needle Cast
Description: Fungal disease of spruce trees causing dieback, thinning and needle loss starting on the lower and inner crown.
Trees Affected: Spruce, Colorado blue spruce is most susceptible
What to look for: Needles turning purplish to brown on older needles, primarily in the lower and inside portion of the spruce and progressing outward and upward.
Treatment Options: Minimize the planting of Colorado spruce (which is very susceptible). Avoid planting a monoculture of spruce trees. Instead plant a variety of pine, fir, larch and other evergreens mixed in with spruce trees. Fungicide sprays can help for some cases, but treatment can be costly and time consuming.