Dissecting microscopy of Aspergillus niger (A. niger), a fungus of the genus Aspergillus. It causes a disease called black mold on certain fruits and vegetables such as grapes, onions, and peanuts, and is a common contaminant of food. It is present in indoor environments as well as in soil. Some strains of A. niger produce mycotoxins called ochratoxins and an isoflavone called orobol. A. niger causes fungal diseases in onion, peanuts, and grapes. Inhalation of large amounts of A. niger spores (found, e.g., in peat dust) may cause fatal aspergillosis in horticultural workers. Image width: 2306 micrometers. Magnification: 43.4x if the image is printed 10 cm wide.