Keeping pie. I made a blueberry pie and am not serving it until the next day. Do I refrigerate?

Rule of thumb for storing desserts: if it has fruit or custard, refrigerate. If not, leave cakes etc at room temp.

Pie is generally fine left out at room temp for a couple days, except for custard pies.

Latoscana, your tart might have "gotten" that mold from something else in the fridge. However, if you had custard beneath the fruit, it certainly needed the fridge.

Sometimes berries can go very quickly. I once made a fruit tart, glazed and refrigerated it, and when I went to take it out of the fridge the next day, it was completely spoiled. Mold covered with currant glaze. Ugh. A cautionary tale, I guess.

Pie is fine left out at room temp for a couple of days

This is not a scientific response, but we try and refrigerate most everything, especially during the summer.

I would refrigerate, I usually wrap in parchment when its completely cooled and stick in the fridge overnight.