Black Mould (Aspergillus)
A common group of moulds appearing as black or dark tufts. Some species release irritating spores, so handle affected material with care.
What it is
Aspergillus is a group of common moulds that can appear as black, dark green, or yellow tufts on substrate. Some species release spores that can irritate the lungs, so it is worth handling with care.
How to spot it
It usually shows as small, dark, powdery patches, often black, on under-colonised or rich substrate. Unlike your white mycelium, it looks dusty and coloured.
Prevention
Sterilise rich substrate fully, work in clean air, and keep a healthy, fast culture so the mycelium colonises before moulds can establish. A dust-free room and good sterile technique are the main defences.
What to do
Do not open or shake a container with heavy black mould indoors. Seal it in a bag, remove it outdoors, wear a mask if you are sensitive, and clean the area. Discard the affected material.