Rose bushes can be a beautiful addition to a landscape; however, the diseases they may contract are not. Black spot, powdery mildew and rust are three common diseases of rose plants.
Identification - Powdery mildew coats the leaves, stems and buds of a rose bush with a white powder-like substance. Rust appears as orange- or rust-colored growth on the underside of the leaves. Black spot appears as black marks. Botrytis blight makes the buds close up and droop.
Treatment - In most cases, fungicides can be used to treat diseases. For Botrytis cinerea, remove all drooping buds immediately.
Prevention/Solution - Many rose diseases can be prevented by planting plants in full sun, where any moisture on the leaves will quickly dry. In addition, a fungicide can be applied as a preventive measure.
Tips - Some varieties of roses are less susceptible to disease than others; when possible, purchase disease-resistant plants. Always follow the care instructions when planting roses in your garden.