tiny black dropping under orchid

[kkdcalgary]

Dear All;

I have noticed in the past month or so that a few of my orchids will have scatterings of black stuff under them when I pick them up to water. At first I thought it was degrading medium but on closer inspection they are tiny cylindrical droppings about 1mm long. The plants are doing fine so I assume it's some sort of insect feeding on the medium. It's happening under my Maxillara tenuifolia and Brassia rex 'waiomao spotless'. Is this something to worry about?

thanks!
Karen.

[Orchid Whisperer]

You may have a problem.

Tiny droppings (green, brown, black, etc.) may be caterpillar frass. Essentially bug dung. The droppings will be small when the caterpillars are small, but will grow larger as the caterpillars grow. Just yesterday I had to deal with a caterpillar, found after finding the frass first.

Caterpillars can be good at hiding. You may need to look closer, or even potentially check for them at night. If it is just a few plants you may be able to control by picking and "squishing". That's what I did yesterday.

I would not rule out other bugs though. If it is only undeneath the pot, it could be cockroach or other bug droppings. Control for other bugs could mean submerging the pot to the rim until the bugs drown or come out, or using a spray.