Black spots on Japanese maple trunk

[Dustbunny]

Hi all,

I noticed black spots on the trunk of my Japanese maple yesterday, and am wondering what they might be.
From researching it seems it could be sooty mould, but when I rub them they seem to have no texture and nothing comes off. I can't see any pests on the tree either.
Other posts suggest a fungal infection..
The spots are between 2-3mm in diameter.

It's not in bonsai soil yet, and has never had it's roots worked on. I moved it to a different position to encourage it to go dormant and it gets a bit of rain where it is and has been a bit wetter than I would prefer, but not really badly.

Any suggestions on what it could be would be great. I'm hoping to repot in the next few days as it's slowly waking up.

Thank you!

[treeman]

Not a good sign. Possibly due to wet roots/ root trouble. Make sure the drainage is perfect, let them dry out between waterings. J maples do not need that much water.
Should be ok if you do that.

[Dustbunny]

ok thanks so much!
I missed repotting last year into proper soil, will repot into bonsai soil asap.