Powdery mildew, caused by the fungus Sphaerotheca pannosa var. rosae is a major pathogen in growing rose gardens. The conidia of the causal pathogen were isolated and collected from Assiut and Sohag governorates, Egypt. The pathological capacity of four fungal isolators was tested on the Eiffel Tower (Rosa hybrida) cultivar, the isolate obtained from Assiut was the most severe infection isolate and the sensitivity reaction of the cultivars were tested using four cultivars of roses i.e., Eiffel Tower (R. hybrida), Multiflora rose (Rosa polyantha), Pine rose (Rosa pinetorum) and Dwarf rose (Rosa gymnocarpa). The cultivars showed varying degrees of significant responses to powdery mildew infection. R. polyantha had the highest disease severity, whereas R. pinetorum had the lowest severity. Greenhouse experiments were conducted to confirm the effectiveness of these fungicides. Six fungicides were tested: Bellis® 38% WG, Collis 30% SC, Dovex 50% SC, Montoro 30% EC, Tilt 25% EC, and Topsin M 70% WP. Both Dovex 50% SC and Montoro 30% EC, fungicide were completely suppressed the disease severity (0.00%) on R. polyantha and R. pinetorum after 45 days in both seasons compared to the control. Two commercial bio-fungicides were used, Bio-Arc 6% and Bio-Zeid 2.5%, which completely suppressed the disease severity (0.66 and 0.83%) and (0.33 and 0.83%) on R. polyantha, (1.16 and 1.16%) and (0.00 and 0.00%) on R. pinetorum, respectively, after 45 days in both seasons compared to the control.