| Looks and sounds like caterpillar poo to me-- I've seen that over and over on other plants, and on a phal venosa hybrid and an oncid last summer. And every time I've seen it, there was always a caterpillar.
If I'm right, one or more tiny caterpillars is hiding in your plant and chomping away.
Inspect it very closely, look everywhere, see what you find hiding. |