IN VITRO AND IN VIVO ANTIFUNGAL ACTIVITY OF EIGHT MEDICINAL PLANTS AGAINST CITRUS SOUR ROT AGENT GEOTRICHUM CANDIDUM

The aim of this work was finding an alternative to the chemical fungicides currently used in the control of Geotrichum candidum, the cause of citrus sour rot. Hexane, chloroform, ethyl acetate and methanol extracts of eight medicinal plants were evaluated for their in vitro and in vivo antifungal activity against G. candidum. Cistus villosus, Ceratonia siliqua and Halimium umbellatum methanol extracts proved to be the most effective, totally inhibiting arthrospore germination of G. candidum at concentrations below 2.5 mg/ml. The methanol extracts of H. umbellatum, C. villosus and C. siliqua exhibited strong antifungal activity with minimum inhibitory concentration values ranging between 0.156 and 1.25 mg/ml, and minimum fungicidal concentration values ranging from 2.5 to 5 mg/ml. Incidence of sour rot was reduced to 0.00, 3.33 and 11.66% when mandarin fruits were treated with 50 mg/ml of C. villosus, C. siliqua and H. umbellatum methanol extracts, respectively, compared with 95% incidence in the untreated control. These findings suggest that C. villosus, H. umbellatum and C. siliqua plant extracts may be effective agents for the control of citrus sour rot. Such natural products therefore represent a sustainable alternative to the use of synthetic fungicides.