This work was carried out under field conditions of two Governorates i.e. Menoufiya and Giza, during two successive sugar beet growing seasons (2013/14 and 2014/15). The efficacy of using extracts of four medicinal and aromatic plants, i.e. Fennel, Rosemary, Marjoram and Thyme extract by three organic solvents (ethanol, petroleum ether and chloroform) on the disease severity of sugar beet powdery mildew was studied. All treatments significantly reduced the disease severity of powdery mildew disease. Rosemary ethanol extract was the best treatment in reducing disease severity in the both seasons at the two governorate followed by fennal ethanol extract. On the other hand, marjoram petroleum ether extract was the least effective one. Also, the application of these treatments increased some crop parameters, i.e. total soluble solids (T.S.S), sucrose percent in root, purity of sugar and root weight.