My young rose bushes look healthy and have started to bloom for the first time, but today I noticed one bush had a few areas on the stems that I'd describe as white and "feathery".

I searched online and saw that the feathery part looks like beech blight or wooly aphids, but I didn't see any sign of life/insects so I wondered if it was a type of mold or fungus.

Can anyone tell me if they know what this might be? TIA -