I like powdered orthene. Easy on humans but still be careful. Kills on contact and is also systemic. It stays with the plant for a few weeks.

What type of orchids? Where are you growing them, indoors or outside?

If your plants are indoors I would suggest a safe pesticide such as Nutria (Bayer) or anything you can find for indoor use.

Jane

Thanks for the replies. I grow Phalaenopsis Orchids as well as a a few Zygopetalums. I grow them all indoors on a windowsill. I live in an apartment and have no access to an outside area (for any type of intense treatment application).

Don't panic!

Whatever they are, just use a natural product which is safe for indoor use. Might be some sort of mites but doesn't look like anything severe. You could spray the plant in the sink with water and wipe off the leaves. Then keep an eye.

Jane