Cytospora Canker on Spruce Trees
Your blue spruce is just reaching maturity when suddenly needles start turning a purplish brown and eventually the branch dies. The problem may be Cytospora canker.
A closer look will confirm your suspicions. Though this disease commonly starts on the bottom branches you may find individual branches dying further up in the tree. Cytospora canker infected trees usually have a bluish white sap on infected branches and the trunk.
This fungal disease is most common on 15 year and older Colorado spruce. There is no cure, but the tree usually doesn’t die. You can usually help minimize the problem with proper care.
Prune and destroy infected branches. Be sure to disinfect your tools with a 70% alcohol or 10% bleach solution between cuts. Mulch the trees to conserve moisture and improve the soil. And water thoroughly as needed during dry periods.
A bit more information: And watch for new research and future control options. Scientists Gary Watson and Karel Jacobs found a tree growth regulator significantly reduced the disease occurrence on treated trees. So, good news may be on the horizon for our spruce trees