And now you want to introduce another way for people to die? You really are eager to get people killed off in this game huh?
The black fungus can only grow under a specific circumstance, at first. You need very low plant diversity; meaning a massive farm that ONLY has carrots would be extremely vulnerable. The black mold can't appear in urban settings or in nature. The incubation period is quite long anyway, so it takes months before it becomes a threat.
I don't mean to nitpick but the picture is of black mold on the ceiling of someone's house. That sounds pretty urban to me.
Well, you see, this isn't the black mold we know and love.
This is Mythrunian black mold.
So to be clear, your saying this would just effect plants and not peoples houses?
the black stuff you see in that image is all just reproductive tissue. It would presumably parasitize the roots of a crop and overtake it after some time; then spread onto other similar crops. They can overwhelm only one kind of plant because they adapted to it when the farmer removed all other plants.
All that said, a house isn't alive, and doesn't have an immune system, obviously. Black mold can use wood... among other things... as food. So yes, your home is at risk... if you allow the mold to infest a field of crops and sit long enough to spread to your house.