Aspergillus niger is a fungus and one of the most common species of the genus Aspergillus. It causes a disease called black mold on certain fruits and vegetables such as grapes, apricots, onions, and peanuts, and is a common contaminant of food.Some people with asthma or cystic fibrosis have an allergic reaction to aspergillus mold. Aspergillus niger is one of the most common and easily identifiable species of the genus. This species is very commonly found in aspergillomas and is the most frequently encountered agent of otomycosis. It is also a common laboratory contaminant.