Like all other plants, rose plants too are susceptible to different kinds of infections. The most common kinds of infections that rose plants are susceptible to are fungal infections, as well as some viral infections. Some of these infections are powdery mildew, which is characterized by the appearance of a powdery formation on the different parts of the rose plant; black spot, which is characterized by the appearance of black spots on the stem and leaves; rose rust, which is characterized by the appearance, on the underside of the rose leaves, a rust colored formation; cankers of the stem/cane, which is characterized by the appearance of cankers and minute black specks; rose mosaic, a viral infection that is characterized by the appearance of mosaic patterns that are bright yellow in color on the leaves; witches broom and rosette, characterized by the quick elongation of the stem initially, followed by the formation of deformed shoots and sometimes a thick and thorny stem; and crown gall, which is characterized by the appearance of irregular masses of stem tissue on the stem close to the soil surface.
Nowadays, it is possible to plant disease resistant varieties of roses, so some of these diseases can be prevented. However, a good curative measure is to use fungicides on the rose plants. Some of the effective fungicides you can use for powdery mildew are triadimefon, thiophanate-methyl, and triforine. For black spots you can use captan, chlorothalonil, triforine, and folpet. You can use mancozeb, triforine, and chlorothalonil for rose rust.
Nowadays, it is possible to plant disease resistant varieties of roses, so some of these diseases can be prevented. However, a good curative measure is to use fungicides on the rose plants. Some of the effective fungicides you can use for powdery mildew are triadimefon, thiophanate-methyl, and triforine. For black spots you can use captan, chlorothalonil, triforine, and folpet. You can use mancozeb, triforine, and chlorothalonil for rose rust.