I have a rose bush with one of the stalk's leaves covered with white spots (not powdery) and some holes. The rest of the bush has none of these symptoms. I can't produce a picture (not technically savvy!). Judie Kreitman email@example.com
Rose Bush Leaves
If the spots move it could be mealy bugs and also could be mites. I would take a couple leaves with the white spots on them to your local nursery and ask them what you are dealing with. Make sure you put the specimen leaves in a plastic bag as most nurseries do not like such things brought into their establishments in an open condition. Once you have positive ID the proper action can be taken.