It might be this:
"Blue Mold Rot Ã¢â‚¬â€œ Most critical disease affecting cherries. It is caused by various molds and begins as a small, round brown spot on the fruit. The pulp underneath this brown spot is moist and a light brownish color. As blue rot mold progresses in cherries, it turns white and forms a bluish-green residue on the outside ultimately rotting the entire fruit."
I don't have any experience with the disease, though. Perhaps you could call a local arborist or nursery and get some advice that would be appropriate for your area.