Sugar beet (Beta vulgaris L.) is one of the most important sugar crops in the world, which considered the second important sugar crop in Egypt after sugar cane. In Egypt, sugar beet is attack by Cercospora leaf spot disease caused by pathogen Cercospora beticola fungal, which caused losses can reach to 40% of yield. In the present study, three plant extracts of Flower of Haloxylon spp, Cichorium spp, and the leaf of Capparis spp were used .Different concentration of the three plant extracts (10%,20%,30%,35% and 40%) previously were used in experiment in vitro to determine Antifungal activity on the linear growth of Cercospora beticola .While in vivo, the concentration which recorded highest effect against Cercospora beticola in vivo were tested. In vivo the experiment conducted in two treatments, the first one sprayed sugar beet plants by plant extracts before the inoculation and the second treatment sprayed plant extracts after the inoculation. Experimental result show under laboratory, all tested plant extracts at concentrations (30,35 and 40%) showed highly effective on mycelial growth of Cercospora beticola and inhibited fungal growth compared to the control treatment and (10 and 20%) concentration. While in vivo result show that the treated sugar beet plants with plant extracts before inoculated then by Cercospora beticola give the best result for reduction the disease severity of CLS disease comparing with the control .In addition to result revealed that the treated sugar beet plants with tested extracts after inoculated by Cercospora beticola gave the best result for value total of chlorophyll a and chlorophyll b which recorded the highest value comparing with the control treatment.