Mildew (condition)

Condition caused by the early stage of growth of any of several types of mold or fungi, appearing as a white to black downy and often smelly film on the surface of organic materials such as cloth, wood, leather, and paper. The two most common species are Aspergillus glaucus and Penicillium glaucum. Mildew is most often found in warm, damp, dark areas and can often look like dirt. It excretes damaging organic acids, such as citric, oxalic, gluconic, etc., that can discolor dyed textiles, paper, paint and leather.