Hello all. Long-time reader, first-time poster. I have a jade plant and another succulent that have been suffering from a brown, withering scale. I know there is a pest that fits this description, but it doesn't appear to be it (from what I've read.) See the photos attached. They get the scale and over time the leaves wither and fall. Any ideas on what this might be and how to cure it? One of my plants has lost ALL of its leaves and is trying, valiantly and with little help from a neglectful owner, to grow new ones. I was told that very dry air in your house could cause this scaling and cracking. Any thoughts?