Because the fungus responsible for the disease survives in the soil, do not plant roses in contaminated soil for three years or longer. Disease Controls Simple maintenance or cultural practices can prevent most rose diseases. Fungicides are necessary only in severe cases. Buy and plant disease-free plants. Choose resistant varieties.
Varieties are available with resistance to powdery mildew, black spot and many other diseases.
See Table 1. Avoid wounding plants during transplanting. Plant roses in areas with good soil drainage and ventilation. Avoid shady spots and dense plantings. This will improve air circulation so leaf surfaces will dry faster, preventing disease infection.