Mites

It is not likely you have mites on your Dwarf Alberta Spruce this time of year. Mites are most active when the temperatures are warm for extended periods of time in the summer on this plant. I see no webbing or eggs on the needles in the photograph although the picture isn’t that sharp enough to determine that. You could take a hose to knock off spider mites without using any remedies. It will also help remove old dead needles inside. The one exception would be eriophiyd mites. That would require being diagnosed by a professional such as an extension agent because they are smaller than spider mites and the damage is different. It would have to be seen in person for an accurate diagnosis. Contact your Penn State Ext. office and they can direct you to the correct agent.