The antifungal activity of citric acidand its salt (sodium citrate) as chemical food preservatives was evaluated against Cercospora beticola in vitro and in vivo. The inhibitory effect of both compounds was studied against mycelial growth of the pathogen in vitro at concentrations, i.e. 0, 10, 20, 30, 40 and 50 mM. Both of citric acid and sodium citrate were able to inhibit the mycelial growth of the pathogen when they were added to the medium at the tested concentrations. Citric acid at 50 mM had the highest effect on the inhibition growth of the pathogen being 83.70% and also had antifungal activity. The percentage of inhibition growth increased as the tested compounds concentration increased. Data also indicate that microscopic examination of treated plates with citrate shows that this treatment reduced the numbers of C. beticola spores on the medium at all tested concentrations and reached its maximum reducing at concentration 50 mM of citric acid compared to untreated plates. The results revealed that spraying of diseased plants with citric acid and sodium citrate either alone or in combination at concentration 50 mM was effective in decreasing disease severity of Cercospora leaf spot compared to untreated plants. The highest reduction in disease severity was observed in case of citric acid treatment. The results revealed that foliar application of these compounds enhanced significantly root yield and sugar percentage as compared to the control.