Help with mould on Japanese Maple

Hi, I've just joined this forum in the hope that someone could help me identify this fungus/lichen/mould? and more importantly give advice on how to treat it and if it is harmful to the tree which I believe is a Japanese Maple.

I'm afraid my gardening expertise is limited to pushing the lawnmower around so layman's terms please.

If it's of any help, the white part of the fungus/mould is a bit stringy like soggy cotton wool or cobwebs if you touch it and the brown part is about 10mm diameter.

Thanks in advance for any help & I hope the pictures get imported correctly as this is my first attempt at it.

Please feel free to move this post to another section as I wasn't sure if it should be in the Trees or Identification section.

 

I'm sorry i don't know but such a great pic of the spider.

 

Hi, I didn't notice there was a spider in my picture until you pointed it out.
I've put the same post on Pistonheads (a motoring forum which has a Home Gardening & Diy section) and they have informed me that it's a scale insect Pulvinaria regalis or Horse Chestnut scale, not a fungus or lichen so I am now sorted. I've since attacked them with a pressure washer.
Thanks anyway, Jeff.

 

I get that each year on my "lollypop" shape acer in our front garden. I spray it with Dilthane, then a week or so later brush off what I can reach when it's turned a bit powdery. Ideally I think I should remove it all and then give it a tar wash before the winter, but it doesn't seem to have any lasting effects. In the past the biggest problem with the tree for me, has been under-watering without realising the situation until the leaves start to burn in the middle of a hot summer. But I'm careful about that these days, so it's not happened for a few years.

 

Advice on scale insect and the possible treatments can be found here :
http://apps.rhs.org.uk/advicesearch/...e.aspx?pid=224