Black fungal growth on skirting board - what should I do?

[conny]

Skirting board needs to come off to see what the back edge looks like.
Did the box contain anything that may have leaked or leached through to the skirting board?
Remove the filler strip around the bottom edge, start prising the board away from the wall in the centre. This will cause the board to bow and then you can work towards the left and right ends. Depending how it is fixed to the wall you can break the gripfill adhesion of possibly snap any nails with a hammer and cold chisel. This will then allow you to prise the board upwards away from the mitred corner joints so you don't really need to disturb the side skirting boards. If it breaks in that area whan taking it out then it needed replacing any way. Bite the bullet and take it off. Spraying with bleach may well be a complete waste of time and effort.

 

[GotGirl]

I moved a cardboard box that was sitting in the corner of a room.
On the cardboard box were loads of tiny creatures.
(Didn't look like spiders or anything else I would recognise.)
Box thrown away.
We have a black stain mark left... see picture at the end.

How shall I treat and repair?
Someone said it's dangerous black fungus.
I should spray bleach on, wait 30 minutes before cleaning with gloves.
Then... dry with a fan for many hours.
Is this good advice?

Drying many hours with fan - surely this would put bleach in the air and would therefore be breathed on surely?

See below for the pic of the item.
Thanks.

Hi there, was wondering if you ever found out what that substance was on the skirting board and what the cause was.

About a week ago I found something on my lower wall and skirting board that looks the same.
There is also a shower and toilet on the other side of the wall and absolutely no leaks.

Its really odd. One week the wall was clean and skirting undamaged. A week later this odd substance appears and skirting is split in multiple places.There was a box standing in front of it with a canvas painting.
Neither the box nor the painting has any damage.

The strange thing is the substance on the wall looks like animal and human faces....like yours.

I've attached a pic.

 

[Alec_t]

@GotGirl
Did you notice this thread is 3 years old? The OP may well not reply.
Your pic shows what could well be dry rot.