Acer trouble

Hi everybody.
First post here, but I wasn't sure where to find out the answers. I did a google and couldn't find a search function on the forum. I'm not a keen gardener but do like to keep it fairly neat and tidy and have a few favorite plants.


I have an Acer Palmatum. Not sure which type as its a few years old.
This year the leaves have grown deformed and there appears to be some white stuff forcing its way from under the bark. Also it appears that whole branches are dying as there are no leaves appearing yet. It has also started to seed, though i don't know if this has anything to do with my problem.
I have attached som pics for you to help with the description

Edit: Just found the search function :dh: but any help still appreciated