black mould is usually aspergillis, the shit grows in shockingly low amounts of humidity, but only blooms when it has lots of water.
if aspergillis gets in your weed you cant smoke it. kill that shit fast.
to kill it, use a rag (CAREFULLY AROUND YOUR PLANTS!!!) soaked wet with a solution of 50% household bleach, 50% water to clean off and eliminate the staining, WEAR GLOVES! then let the room dry completely. after the room has fully dried, fill a bowl with cheap gin, straight up, no rocks, no twist. using a clean dry cloth, soaked in the cheap gin, wash the walls of your growroom. cheap gin works as well as bombay saphire or rangpur lime, so use the cheapest shit you can get. the gin has natural anti-fungal powers, and wont cause issues with your dope. the shit can kill a leaf outright if it gets on your plant, so apply it carefully and wash the whole wall well, soak the wall good. let the gin dry on the wall and the black mould wont come back for a while. youll have maybe 2 months before it can bloom again. hopefully youll be able to finish your grow without any black mould on your buds. after that,a serious antifungal pain is needed. several coats of it. none of that hairy fairy hippy shit either, you want copper methycote and scary health warnings.