The effect of Sodium bicarbonate and three oils namely; garlic, anise and mineral oil individually and combination of Sodium bicarbonate + mineral oil were tested for their effect on powdery mildew of Matricaria chamomilla under greenhouse and field conditions. Disease severity was significantly reduced by all treatments in both greenhouse and field. Flowers number in greenhouse under infection of powdery mildew disease was highly significant in treatment with NaHCO₃ + mineral oil followed by Garlic oil and NaHCO₃. Fresh weight of flowers was significantly higher in NaHCO₃+ mineral oilfollowed by Garlic oil (5.24 and 3.45 g) compared to control (1.7g) respectively. On the other hand, dry weight was increased significantly in treatment with NaHCO₃ followed by Garlic oil (0.81 and 0.54g) compared to control (0.21g) respectively. Effect of sodium bicarbonate and oils on flowers fresh and dry weight and plant height under natural infection of powdery mildew in the field, was significantly increased in treatment with NaHCO₃ + mineral oil followed by NaHCO₃ (663.13 and 451.13g) compared with control (220.77g); respectively. Dry weight of flowers after 2 weeks was highly significant in treatment with NaHCO₃ followed by Anise oil (120.67 and 94.33g) compared to control (41.67g); respectively. On the other hand, after 4 and 6 weeks treatment with NaHCO₃ + mineral oil was the best treatment in fresh and dry weight followed by Anise oil.