Bush killer

Your bush looks like a Cherry Laurel and the white you are seeing is a type of sucking insect called scale (white prunicola scale). It can be difficult to control.
The first thing you should do is remove all the dead wood and leaves and see what you have left.
Here is a recent blog post from us about this and what to do:
https://marylandgrows.umd.edu/2019/09/25/qa-what-is-this-white-growth-on-my-cherry-laurel-shrub/


Christine