Abstract: Background and Objective: Mediterranean fruit fly (MFF), Ceratitis capitata and peach fruit fly (PFF), Bactrocera zonata are the most economically significant pests threatening Egypt's horticulture crops. Therefore, the present investigation aims to study the forecasting of female and male periodical appearances, female field generations as well as the interaction among both sexes as a base for taking action on fly-control measures. Materials and Methods: Periodical appearance of males and females of both species in mango, apple, plum and navel orange orchards in the Egyptian agroecosystems were studied in 2019 and 2020, using sex and synthetic olfactory attractant traps synchronized with certain abiotic factors. The data were subjected to CoStat Software (2008). Results: MFF females appeared earlier than PFF females on apple host, with a discrepancy between them on some hosts from one season to another. A positive relationship was recorded between activities of MFF sexes all along the study as well as between PFF sexes in the first season. No clear relation was found between fruit fly species activity and weather parameters. MFF and PFF females had numerous generations per year, four to six generations for MFF and three to five for PFF. Conclusion: This study clears the periodical appearance of males and females of PFF and MFF in the field under Egyptian agro-ecosystems, this information could be helpful in forecasting and controlling actions in orchards of these fruit species.