Hi Shannara:

I agree with starting with a systemic fungicide. I don't think your problem is from scales but even with the photo, a more detailed description would help. For example, are the spots dark brown or black? Are the dark areas (spots) raised or sunken? Is the upperside as affected as the underside of the leaf?

While you are treating, please remember to isolate the plant and sterilize tools, etc to avoid contamination of other plants. Allow for good ventilation and monitor temperature as well as moisture.

Best of luck,
Dail