Spots on base of Den Smilliae Leaves

[KatieM]

Hey everyone. I've got a nice big Den Smilliae with some white and black spots on the underside of the leaves, only at the base. It doesn't appear to be mealybugs. The white is almost hard. Possibly scale? Scale is the one pest I've not experienced so any advice would be much appreciated. I have also noticed some black almost mildew looking stuff on some of the older canes. Not on the newer growths.

Care:

Zone 9a
Outdoors southwest facing screened lanai, moderate light.
Water before completely dry but do not keep it overly damp
Plenty of Florida humidity

I've hit it with physan, wiped off the white specs with rubbing alcohol 70 and a qtip but back they came.

Thoughts and advice are much appreciated!