Why does bread mold faster in dark areas?

Most molds are very sensitive to the radiation in sunlight, and its growth is inhibited when exposed to it. Other considerations are temperature and humidity. Most molds that we study grow very well in dark, warm (room temperature or slightly above), humid conditions. These are easily duplicated on the cheap and easy by sticking it in a plastic bag with a drop or two of water, and place it in a warm dark corner. These differences can be beneficial if you want to cultivate a particular mold that grows well in radiation, or very cold, or very hot, or very dry or other adverse conditions.