If you go into a walk in humidor and notice a slight whitish fuzzy dusting on some of the uncovered cigars, usually Maduros, that is called Plume. Mold on the other hand is blueish green or other colors. The plume that you see is telling you that the humidor is doing its job. The oils in the wrapper on the surface slightly crystallize after being stored for some time. Mold is not good, and can contaminate other cigars in your humidor.
I tried to take a picture of this but I have an older iPhone and have not upgraded the super stud phone 3.0. The cigar in question, a Super Toro in Maduro was hand rolled in house from Up-In-Smoke cigars in Cromwell, Ct.