We have an ornamental tree in our garden and it is completely covered in white little dots. They look like eggs or larvae, but I’ve never managed to see them move.
This is in Spain in case that’s relevant. More pics in comments.
Got this from a reverse image search.
http://www.plantsgalore.com/care/insects/Insects-scale-euonymus.htm
Thanks!
With any scale insect make sure that ants are not actively tending them. It’s a mutually beneficial arrangement like ants and aphids. Often controlling the ants will let the natural predators clear them out.
You can also release many options for predatory insects/wasps that will clear them out. Using a native species is usually best. They tend to stick around for years and get rid of the problem long term.