Role of essential oil components on the resistance of citrus fruits to Penicillium spp.

Infections by Penicillium digitatum (Pers) and Penicillium italicum (Wehm), the most harmful post-harvest citrus fruit pathogens, usually occur through flavedo micro-injuries. It may therefore be assumed that pathogen spores come into contact with essential oils. The study examined the effect of essential oil composition on P.digitarum and P.italicum growth. The essential oils of lemon (Citrus limon cv Femminello) harvested in three different periods and of six orange cultivars (Citrus sinensis cvv Washington navel, Sanguinello, Tarocco, Moro, Valencia late and Ovate) were extracted and analysed. The antifungal efficacy of the oils was then examined by serial dilution assay against P. digitatum and P. italicum. The results show a positive correlation between the oxygenated monoterpene content of the oils and the pathogen inhibition. Moreover, P.digitatum was found to be more sensitive to the inhibitory action of the oils.