Does your fungicide work on a Colorado blue spruce that has Rhizosphaera (our best guess based on the description of purple needles)?
If your Colorado blue spruce has Rhizosphaera, our Final Stop Disease Control and Fungicide will not work. The best control for that disease is prevention. Cut / prune dead branches, make sure water is draining from area and well fertilized. We recommend seeking a professional horticulturalist to get a true diagnose.