All tested pepper cultivar differed in their response to powdery mildew infection. Gedion Cv. was very susceptible (76.92 %), while Atol Cv. was the least susceptible one (12.55 %). A positive correlation between cultivars susceptibility and the number of stomata on both leaf surface was noticed. Atol Cv. was the least susceptible, whereas the number of stomata on the upper surface (25.3) and the lower surface (149.4)/cm2. Gedion Cv. was the highly susceptible, it was containing on the uppersurface (184.0) and the lower surface (390.7)/cm². Score at 800 ppm and Emininte at 1000 ppm were inhibited the conidial germination and germ tube elongation, whereas the fungicides were highly toxic, while Topsin M was the least effective one. Score followed by Emininte were most effective fungicides in controlling the disease severity of pepper powdery mildew from 49.4 to 8.1 and 5.8 % respectively. While Topsin M was less effective one (38.0 %), as improved the plant hight, fresh and dry weight and increased the yield from 35.6 to 62.3 and 66.6 kg respectively in comparison to Topsin M (41.7 kg).