Most rose diseases are caused by attacks on your plants by different kinds of fungi. The good news is that no matter what type of fungi is damaging your roses, the treatment options are virtually the same.
To start, there are several things to do to prevent your roses from attracting fungus. One way to avoid attracting fungi is to water the soil, not the actual pant. Fungi will be attracted to any moisture on leaves, blooms and stems. Check on a regular basis for exposed canes because fungi can find its way into the plants this way.