Today, synthetic fungicides are the primary means for controlling postharvest diseases of citrus fruit. The use of synthetic fungicides to control postharvest diseases has many limitations and disadvantages, such as developing resistance in disease-causing microorganisms and social rejection. Accumulated pesticide residues that remain in fruit and vegetables are a major public health concern to consumers. The global trend has shifted towards the reduction of synthetic pesticide application in agriculture in general and in postharvest in particular. Currently there is a growing interest in using natural antifungal compounds, like plant extracts for the preservation of foods. Penicillium moulds ( Penicillium italicum Wehmer and P. digitatum Sacc) are major causes of citrus fruit decay. In order to develop fungicide formulation of natural origin as postharvest treatments, this study was conducted on the antifungal activity of pomegranate ( Punica granatum L.) extract and essential oil in in vitro and in vivo conditions against P. italicum and P. digitatum . The first experiment was done in Petri dishes to compare different concentrations of extract and essential oils by incorporating them into the potato dextrose agar (PDA) culture medium. The second experiment was set up according to a complete randomized design with 4 replications and tests in ‘Satsuma’ mandarin. The changeable factors include extract concentration (0, 25%, 50%, 75% or 100%) and the effect of treatments (preventive or curative). The fruits were wounded on the outer surface on four locations to a depth of 2 mm and a diameter of 1 mm. Nine mandarins per treatment were used. Preventive treatments were carried out by dipping wounded fruit into the specific formulations of extract and thereafter, each wound site was infected by inoculating 20 ?L of the inoculum of P. italicum or P. digitatum . For curative treatments, fruit were wounded as above, and then inoculated with P. italicum or P. digitatum (20 ?L of inoculum per wound site). Even though data showed no significant differences between pomegranate essential oil treatments, the pomegranate extract at 2000 and 2500 ?l elicited a significantly lower spore germination under in vitro conditions compared to the other treatments. The results showed that 75% or 100% pomegranate extract reduced percentage infected wound, lesion diameter and fruit weight loss and increased phenolic compounds and phenylalanine ammonia-lyase activity in ‘Satsuma’ rind. The obtained results showed that the tested pomegranate extract can be effectively utilized for controlling and curing infections caused by P. italicum and P. digitatum. Keywords : Antioxidants, Biotic stress, Phenolic compounds, Postharvest.
