Honeydew on leaves, unknown source

[3rdMaestro]

This one has me scratching my head a bit. On several of my orchids, I occasionally find little drops of sticky, clear liquid (I think its called honeydew?) But it's only on new growth, and I really can't find any evidence of insect infestation. The droplets are also limited only to new growths. Any ideas what might be causing this? Could some kind of infection do this? The orchids that have it seem quite healthy otherwise.