Fruit flies impact the production of many fruit species and cause economic yield losses in all countries in West Africa. In such endemic areas, including metropolitan cities, fruit flies do not occur only in orchards but extend their infestation to trees in household backyards, private gardens, and stockpiled fruits for local and international markets. This scenario occurs in almost all towns and cities in Nigeria, contributing to fruit fly population explosions if left uncontrolled. We, therefore, attempted, for the first time in Nigeria, to implement a mass trapping technique over an area of about 20 km2 to capture mainly fruit flies infesting mango and other major alternative hosts. This study evaluated the population dynamics of the major mango fruit flies Bactrocera dorsalis (Hendel) and Ceratitis cosyra (Walker) during on and off season periods in Ibadan metropolis, Nigeria. The influence of environmental factors, such as temperature and humidity (rainfall), on the abundance of both species was also evaluated. Results of the implementation of fruit fly management techniques, which included orchard sanitation by picking dropped fruits, mass trapping using parapheromones, and the application of protein baits, are discussed. B. dorsalis dominated the trap catches, whereas the presence of C. cosyra on mango was very negligible throughout the study period. Although a higher number of C. cosyra was observed in the dry season months of January–March, it was totally absent in other months. The presence of B. dorsalis was recorded throughout the year, with higher populations occurring during the rainy season. The relative abundance of B. dorsalis across alternative hosts indicated that Irvingia harbored higher fly numbers compared to citrus. Fruits incubated during first- and second-year harvests showed a significant 350suppression of fruit fly populations by not less than 70%–82% for B. dorsalis and C. cosyra, respectively, in all fruit species compared to areas where no control was applied. Fruit fly population dynamics are influenced by environmental factors. Application of management strategies in a metropolis that is characterized by polycultures and diverse hosts can suppress populations. However, there is a need for awareness campaigns aimed at communities in the metropolis for their direct involvement in the control of fruit flies.