Antifungal activity of Moroccan medicinal plants against citrus sour rot agent Geotrichum candidum

Aims:  The aim of this work was to find an alternative to the chemical fungicides currently used in the control of Geotrichum candidum , the causal agent of citrus sour rot. Methods and Results:  Minimal inhibition concentrations (MIC) and minimal fungicidal concentrations (MFC) were determined using agar dilution method. The methanol extracts of Cistus villosus , Ceratonia siliqua and Halimium umbellatum exhibited strong antifungal activity with MIC values ranged between 0·156 and 1·25 mg ml −1 , and MFC values ranged between 2·5 and 5 mg ml −1 . Incidence of sour rot was lowered to 0·00, 3·33 and 11·66% when mandarin fruit was treated with C. villosus , C. siliqua and H. umbellatum methanol extracts at 50 mg ml −1 , respectively, compared with 95% in the control. Conclusions:  Cistus villosus , C. siliqua and H. umbellatum methanol extracts successfully reduced the disease incidence caused by G. candidum , and no phytotoxic effects were recorded on citrus fruit. Significance and Impact of the Study:  These findings suggest that C. villosus , C. siliqua and H. umbellatum plants may be useful and effective agents for control of citrus sour rot. Such natural products therefore represent a sustainable alternative to the use of synthetic fungicides.