Amazingly, pure peppermint oil scrambles the senses of insects, leaving them disoriented, unable to breed, feed or breathe. We have actually seen aphids land on treated rose buds, scramble around for 15 minutes and fly away! Add to that, pure canola oil as a miticide and potassium bicarbonate as an organic buffer. Please test first on ornamentals. For best results, water well in the a.m. Then at dusk, spray a fine even mist on leaves top and bottom canes and if you have blackspot) the soil at the base of the rose. Do not overspray.