Black mold
Crop: Onion Disease: Fungal Pathogen: Aspergillus niger
SYMPTOMS AND SIGNS
DISEASE DEVELOPMENT
DISEASE MANAGEMENT
- Post-harvest black discoloration at neck; lesions on outer scales; black streaks under outer dry scales; entire surface of bulb turning black and shriveling.
- Below the dried skin a powdery, black mass of spores forms which is often invisible on the outside. The spores can be present on each of the scales. Infected scales first appear watery, after which white, fluffy mycelium appears on which black spores quickly form. In advanced stages, the bulbs will start to shrivel.
- The region below the neck blackens and clusters of black fungal spores from along veins and on or between the outer papery scales of the bulbs. Infected tissues are water-soaked and dry and shrivel over time. In advanced stages of the disease, the entire surface of the bulb turns black and all the scales are infected. Discoloration extends from neck to the central fleshy scales and the disease is usually associated with soft rot bacteria.
- Black discoloration at neck; lesions on outer scales; black streaks under outer dry scales; entire surface of bulb turning black and shriveling.