I bet it was spider mites. They seem to love attacking Alberta spruce. Or, was it winter damage? Knowing the cause and helping to prevent it from happening again, will keep rest of the spruce looking good. As for the dead spot, unfortunately, there really is nothing you can do. At least, nothing fast. They grow slow and it will take time for the spot to fill in. I wouldn’t go overboard with fertilizer. That could cause other problems. Keep an eye out for spider mites and be ready to attack them and win that battle. And, water well going into winter.
Thanks for writing!