@arfonzo.eth
Do a 3:1 ratio (3 parts water to 1 part soap), or even 2:1. Make sure your spray bottle is laying it on thick enough! Really, don't be stingy, douse the whole affected area until it's literally dripping with soap. A few drops ain't gonna do it!
It shouldn't harm the rose. At least we never have, with our detergent spray!