Current study aimed to study the population density of two serious insects infesting many varieties of fruits; The Mediterranean fruit fly (MFF), Ceratitis capitata (Wiedemann) and The peach fruit fly (PFF), Bactrocera zonata (Saunders) (Diptera: Tephritidae) on three different fruit varieties; mango (Mangifera indica L.) Alfonce var., guava (Psidium guajava L.) Baladi var. and grapes (Vitis vinifera L.) Red grape (Filam var.). Experiments were carried out during two successive seasons 2022-2023 at Nobarya zone (Behera Governorate) using white Jackson traps starting from March month until November month and data represented by catch/trap/daily of males on the successive three varieties of fruits. During both of the two successive seasons the population density of MFF was more than PFF in both of the three successive of fruits. At the first season 2022 C. capitata population increased gradually to reach to the highest peak on the 1^st of July with mean numbers of CTD (21.1) flies on mango trees, (25.3) flies on guava trees on 23^th of September month, and (32.5) flies on grapes trees on 24^th of May month. While for the second successive insect B. zonata the population increased gradually to reach to the highest peak on the end of June month with mean numbers of CTD (17.3) flies on mango trees, (13.0) flies on guava trees on 28^th of October month also, whereas it was (10.8) flies on grapes trees on 15^th of May month. As the same trend was achieved at the second successive season 2023 whereas C. capitata population increased gradually to reach to the highest peak on 12^th of July month with mean numbers of CTD (25.2) flies on mango trees, (30.5) flies on guava trees on the end of September month whereas it was (35.2) flies on grapes trees on the end of May month. Whereas for the second successive insect B. zonata population increased gradually to reach to the highest peak on the 26^th of June month with mean numbers of CTD (19.5) flies on mango trees, (15.0) flies on guava trees on the 4^th of November month also, whereas it was (11.5) flies on grapes trees on 8^th of May month.

Statically analysis show that C. capitata and B. zonata populations were significantly higher on guava orchards than on that on mango and grapes orchards during both of the two successive seasons of investigation. On the other hand C. capitata population was significantly higher than B. zonata on both of the three crops; mango, guava and grapes during both of the two successive seasons. Also, there were inversely correlations between B. zonata and C. capitata populations on both of mango, guava and grapes orchards during both of the two successive seasons; however the correlation coefficient values (r) between their populations were negative.