ABSTRACT
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.
