What’s wrong with these Dendrobium leaves

[sfunding]

I have three dendrobium plants exhibiting something I’ve never seen. Leaves are rough and white/gray. It doesn’t wipe off with alcohol on a cotton pad.

Note: I had to leave home suddenly for a family emergency and the south Florida humidity would have to be the source of water. I didn’t know I’d be gone nearly a month. Most plants didn’t suffer much, if at all. So, I’m hoping this is dehydration that can be remedied with time.

[estación seca]

Welcome to the Orchid Board.

That is almost certainly spider mite damage. They are active when it's hot and dry. They may be mostly gone if it's been rained on recently. I would spray all surfaces of the plant, surface of the medium and pot with isopropyl alcohol 70%, rubbing alcohol. Going forward, wetting the entire plant once a week limits their activity. You can't get rid of them because they are in the landscape around you everywhere, so you must be watchful.

[Paphman910]

Mite damage. I would spray with 2% solution of horticulture oil. The false spider mites are really hard to control.