Needle Cast on Spruce
Purple needles turning brown and branches dying on spruce may mean the tree is infected with needle cast fungal disease.
This disease is usually not deadly, but it certainly ruins the beauty and the screening value the trees provide. Contact a certified arborist or your local extension service for a definitive diagnosis before treating. Several diseases can cause these same symptoms.
Make sure your trees receive sufficient water during dry periods, mulch the soil and give them plenty of room for light and air to reach all parts of the plant.
Promptly remove and destroy infected branches to help slow the spread of this disease. Disinfect your tools with a one part bleach and nine parts water solution or 70% alcohol between cuts.
Organic fungicides labeled for controlling this disease can be applied when new needles are about half expanded and again 3 weeks later.
A bit more information: Use needlecast resistant evergreens like arborvitae, junipers and pines to replace any diseased spruce you decide to remove. Provide sufficient space for these plants to grow to full size. Temporarily fill in voids with ornamental grasses and perennials. Remove these as the maturing evergreens need more space.