The most important management for high yielding production is nutrition management, but it may affect the response of peach trees to Ceratitis capitata insect. This experiment was carried out to evaluate the effect of different mineral fertilizers Bio max, Thiosilicon and the mixture of them) on increasing the defense mechanism of peach trees to infestation by the Med. fly C. capitata in the field. In this study 5 concentrations were used Bio max and Thiosilicon (0.05, 0.1, 0.2, 0.4 and 0.6%) and mixture of them was used (0.2 Bio +0.2 Thio, 0.4 Bio +0.2 Thio and 0.2 Bio +0.4 % Thio) there were applied in two separated sprays (1 and 2) and at three times intervals (3, 5 and7 days). The obtained results showed that in spray 1, the mixture of the two compounds recorded highest reduction % of infestation by C. capitata and in spray 2, Bio max recorded highest reduction % of infestation. In spray 1 highest reduction % of infestation was obtained at three days interval while in spray 2 the best reduction % was obtained at seven days interval. These results concluded that the used mineral fertilizers enhance peach trees in controlling C.  capitata,as the silicon, once absorbed by the xylem veins, is deposited on the wall of the plant tissues, forming a mechanical barrier. This control tactic increased the obtained yield.