My PC is down, so I can't post a photo, but I thought I'd describe this "problem" (or maybe not...) and see if anyone knows what it might be. My subquintplinervis (a species that looks, to me, just like pottsii) gets these flaky, light brown, flat (not scale!) spots on the oldest leaves. It's so weird - I'll take it down and water it, see the spots, wipe them off and the next time I go to water it, there they are again! I'm pretty sure it's not a pest - I see no signs of damage. The "spots" seem to rest in the "pores" of the leaves, and it's easiest to remove them by spraying the surface with some water, then using a soft toothbrush, gently scrub the surface and - voila - they're gone. If I skip brushing them off for a few waterings, there gets to be quite a lot of them. And, as I said, they're only on the oldest leaves and, as newer leaves start to age - you know, become more succulent and less shiny - I start seeing a few of these flaky spots on them. Does ANYone have an idea of what this might be??
Denise in Omaha