you can buy Rose Defense By Greenlite at Home depot or your local nursery,, Or spray with neem oil, all are organic. OR you can put in a water sprayer > fill almost full with water,, 1 tablespoon of joy dish soap, and Tobasco sauce( several shakes), shake well and spray.
Spray the leaves upper and lower and ALWAYS first thing in the morning before the sun gets hot or it will burn the leaves. Use that method for any of the sprays.