Experiments were conducted on peach trees Prunus persica (Fam.: Rosaceae) at Nobariya region (Behera Governorate) throughout two seasons 2020 and 2021 to experiment different ways on controlling the serious pest Peach Fruit Fly (PFF) Bactrocera zonata (Saunders) (Diptera: Tephritidae) on peach trees through study the comparison between effect of two compounds, Lanthanum Chloride (LaCl3) and Triacontanol Hormone (TRIA) on the infestation degree by that insect. Experiments were carried out by two concentrations of Lanthanum Chloride (1 ppm and 5 ppm) and two concentrations of Triacontanol Hormone (35 ppm and 50 ppm). Peach trees were sprayed by the two successive substances three times at the same time, 21 days between each of them. As data obtained indicated to that Lanthanum Chloride were more efficiency than Triacontanol Hormone on controlling the successive insect whereas mean numbers of B. zonata was decreased on peach trees when treated by Lanthanum Chloride more than when treated by Triacontanol Hormone. The data obtained showed also the effect of the low concentration of both of the two successive substances were more efficiency than the high concentration of the same substances and vice versa, the high concentration of both of the two successive compounds led to negative effect of the infestation by the successive insect.