Mini Rose Bush Question

Mini Rose Bush Question

Hi, I'm new to the community. I moved from Chicago to LA (entertainment industry) and had to give up most of my plants. I was gifted a mini-rose bush a couple months ago. I re-planted it and set it where it would get a lot of afternoon sunlight. It seemed to be doing really well. Earlier this week I noticed the newer leaves seem to have some sort of white powdery substance on them. What is this, and what needs to be done for treatment?
My Room

My Room

Gardens in the rain

Gardens in the rain

Garden Pic spam – not for the fainthearted or those with dial up…

Garden Pic spam – not for the fainthearted or those with dial up…

Three unknown trees with berries

Three unknown trees with berries

my apartment

my apartment

ID Help?

ID Help?