we don't have too much trouble with bugs on the orchids, actually all the lizards and birds keep the bugs at bay here. I have fewer bug problems outside than I did growing inside a screened porch. I think the benefits of sunshine and rainwater far outweigh the potential bug problem.
I recall being terrified of slugs getting on my phals, but that has been only once in a while. The gravel in the slat house floor really ended that problem.