Bugs on Orchids
I've suffered with these bugs/aphids/ something for several years! I've been to 2 different nurseries, have applied systemic and spray for everything like rust, scale, aphids, mites, you name it, I've tried it and can't get rid of these "buggers"! They are knocked back then return. They spread to the other orchids and plants I have nearby. HELP!
It looks like you may have Mealy Bugs. Refer to the two facts sheets from CSU Extension and Plant Talk Colorado below for tips on management.
Since you already have tried so many different products without success and the insects are spreading to other plants, you might try popping it out of its pot, washing off the roots, discarding the soil, disinfecting the pot and repotting it with fresh soil.
If nothing works, you may want to consider discarding the entire plant.