Centipedes?

[StephaneL]

I found many of those bugs in the medium of one of my orchids and I am not sure what they are. They are about 7-8 mm long. My first thought is that they are centipedes, but I don't see the antennas centipedes usually have.

Do you know what those are? Are they damaging to my orchids? Do you know how to get rid of them?

Thanks!

[Roberta]

I have seen critters like that in Cymbidium pots that should have been repotted a couple of years prior where the mix has turned to mud. I suspect that they damage roots. But they're a sign of bad mix. The way to get rid of them is repot!

[Subrosa]

There are 2 pairs of legs per body segment, so that's a millipede not a centipede. Centipedes are fast moving predators on other bugs, so they're actually good to have around. They can give a painful bite though. Millipedes like that are slow moving detritivores, eating decomposing organic matter. Repotting should eliminate them.

[StephaneL]

Thank you both!

I think Subrosa is correct. I searched a bit more after the response and they indeed look a lot like "garden millepedes".

The plant is a Vanda falcata I bought in the fall. I was waiting to repot it in the spring, but I guess I will do it immediately.

[Roberta]

I think you should be able to safely repot Vanda (Neofinetia) falcata now. The traditional Japanese approach uses sphagnum to make the "moss mound" but importantly, the technique requires an air pocket in the middle, very important if using that approach. (So not obvious!) I would suggest, instead, the use of medium bark. Keep it simple. These little Vandas need fresh air in their root zone, and humidity rather than "wet", like all Vandas. If the medium is broken down enough to be friendly to millipedes, it is a bad place for a Vanda. Definitely repot, don't delay.

(I sometimes use sphagnum especially for the smaller Neos, but not in the Japanese style - I pack it loosely, in a plastic basket, so that it is very airy and dries fairly quickly)

[smweaver]

Yes, that's a millipede, as Subrosa indicated. One of the other differences between millipedes and centipedes (not that you may want to test this with a centipede) is that millipedes defend themselves chemically. Pick one up and then smell your hand. You actually will probably not even need to move your hand close to your face before detecting the scent that a millipede will emit to deter predators. When I find millipedes (often after watering), I gently pick them up with a pair of forceps and toss them outside. They are (like the vast majority of insects) beneficial.

[StephaneL]

Despite Roberta's recommendation I will try the traditional Japanese approach. I specifically bought a cheapish seedling (rather than one of those crazy expensive named varieties) specifically to be able to test this method.

[Roberta]

Originally Posted by StephaneL

Despite Roberta's recommendation I will try the traditional Japanese approach. I specifically bought a cheapish seedling (rather than one of those crazy expensive named varieties) specifically to be able to test this method.

Just be sure to make that "pocket" in the middle... either use a small pot or cup, or build your "mound" on a narrow-necked bottle (like the old-style Coca Cola bottle) Here's a video on the traditional method for Neofinetia falcata potting by Jason Fischer of Orchids Limited, an expert on Neos (He's one of the very few Americans who is invited to judge them in Japan, he does know his stuff) Repotting Neofinetia falcata

[StephaneL]

Well, there was two separate plants in the pot so I'll be able to run an experiment and compare the traditional Japanese approach against bark.