Identification: Help? Strange Bugs / Growth on Acer?

Hi - Can anyone identify these strange bugs / fungus / growths (?) on my Acer. Are they harmful? I had a similar thing on a Twisted Hazel a few years ago, which we no longer have. What is the most effective way of treating it? Thanks, Erica

 

Looks like some kind of scale insect or mealy bug. If so the best things is to wash them off. Otherwise I believe Neem oil is recommended.

 

Thank you for your help, its appreciated : ) Kind regards erica

 

Horse chestnut scale. Brushing them off helps to control them. Quite prevalent in the UK now but the damage does not seem to be serious, more of an appearance thing.

 

might want to put on a good spray of water on the growth to blow them off, usually scale comes with other insects that might cause more probs.....keep watch ~

 

Thanks everyone : )