Maple branch problem

I wonder if anyone can help with a problem on a Seiryu acer. I have two Seiryu acers, both in pots, one of them has an unsightly crust or scab forming round a leaf and branch joint. This crust or scab can easily be removed with a finger nail. It is a light green in colour, The crust, not the finger nail. I have several more acers of different species, and non of them have this problem. I hope someone has some advice, Thank You.

 

Hi, can you post a picture?

From the description it sounds like it could be lichen, which is entirely harmless to the tree.

 

Thank you for the quick reply maf. I will take a photo and try to put it on here. I've never put a photo on here before, so I will have to check how to do it. I think you are right about the lichen. Thanks again.

 

You're welcome.

Here is a guide for adding pictures: How to Attach Photos and other files

 

This should be a photo of my maple branch problem

 

For a comparison, does it look anything like this picture of lichens on a 'Sango kaku'?

 

That's just like my problem. I think you were right first time. Thanks for that.

 

Very common over here and can be quite unsightly and off putting