I suspect that your blue spruce is infected with a fungus that causes Leucostoma (Cytospora) Canker. This disease usually affects trees older than fifteen years old that are stressed by drought, winter injury or other diseases. To control Leucostoma Canker remove infected branches. Do not prune affected trees during wet weather because spores from the fungus can be released at this time and may be carried to other branches. Also sterilize your pruning tools before moving on to a different tree or before you put them away. Improve your trees’ vigor through additional waterings, weed control, and fertilization.

The University of Wisconsin Extension has an article that may prove helpful. The article can be found here: Cytospora Canker – Wisconsin Horticulture

Thank you for your question and have a great gardening season..