Are these scales?
Yes, and that looks like a pretty heavy infestation.
Take a look at our page on Euonymus Scale here, for suggestions on control:
There may be a good bit of dieback if this has been going on for years. We don't recommend planting Euonymus japonica, and if you choose to replace with Euonymus, we'd suggest E. kiautschovica where possible.
Thank you. Have had these for over a decade and just noticed. Middle plant is barely alive and the 2 on each side are covered with these scales.
Thanks for the advice. Will be looking to replace them!