Posted: 21/07/2013 at 11:54
If you can't scrub them off with a stiff brush, the only insecticide which will work against scale insect is a systemic one which is absorbed into the plant like Provado ultimate bug killer. It will take a long time to work and may need repeat sprayings.
Looks a bit like a Bay tree, but not sure.
Edit: Just saw your reply which appeared as I was replying. Scale insects suck the sap of the shrub and weaken it.