I have an old antique running rose bush that I have let run wild along my fence, it is beautiful when in bloom. These roses usually have a long blooming season if you keep the spent blooms cut back. I was gone for a few days and when I returned I realized the roses were no longer blooming. I started cutting the spent blooms off and discovered that there was a problem. The roses never finished blooming lots of the buds had wilted and died. I was quite confused and started looking for something that could have caused this. I found the blooms and buds covered in a white powdery looking mass. They also had some small webs across the leaves. I learned this is mites and they can kill plants, shrubs and trees, where ever they attack. After some research I found to destroy this insect, trim off all the infected parts, spray with liquid sulfur. Burn or destroy these cutting to prevent further infections and damage. If the infection is small spray with water to wash them off.
I have seen it on other plants and trees. It can kill any parts that are infected. Some friends have lost parts of trees and some shrubs as well as outdoor potted plants.