Problem with Dendrobium Orchids Bugs!

[tabemasu88]

Hello,

I search on the forum but couldn't identify the kind of bug I have. I only find the small black beetle bugs, but i don't think its the small black beetle bugs.

I find some small, long, skinny, black, wingless bugs on my Dendrobium Orchids. I am wondering what is the cause. I water when the pot is dry, and there is enough light. Also it is planted in a small pot about 4" or so.

This Dendrobium Orchids is my second one that I plant. The frist Dendrobium Orchids has the same problem and there are like 50+ this kind of small bugs on the stems, leaves, so i just throw the plant out, but it happen again on this plant. There are only 2 or 3 noticeable bugs on the leave and stems right now

Also, I use the bark type planting mix to plant them.

Thanks