Can you identify growths on acer?

I am hoping you can identify and advise on the enclosed samples of fungus growing on a large tree in my son’s garden. I’m not sure of the name of the tree, so I’ve enclosed leaves as well.

A: The tree is Acer palmatum, a highly variable and usually small-growing Japanese species from which many superb garden varieties have been developed. The leaves you enclosed are green, but Japanese maples also come in a wide range of foliage hues from gold or variegated to a rich purple-bronze. And they all fire up superbly
for autumn.
What look like fungal growths are crusts made by scale insects. The part you see is the waxy protective scale which the insects produce to protect themselves. They may not look very lively but underneath that tough exterior, the insect is sucking sap from the plant.
On a large, healthy tree, a light infestation will do little harm, but if the insects become too numerous or if the tree becomes stressed and weakened, they can be damaging. Insecticide sprays are unlikely to penetrate the scales, but if there are not too many, you can rub them off by hand. If you use a coarse cloth such as sacking or an old kitchen scouring pad, the job is easier.