El-Afify, A.H., R.M. Shreef, M.A. Hendawy and N.M. Ghanim. 2023. Seasonal Activity of Bactrocera zonata (Saunders) and Ceratitis capitata in a Navel Orange Orchard in Dakahlia, Egypt. Arab Journal of Plant Protection, 41(2): 98-104. https://doi.org/10.22268/AJPP-041.2.098104 The peach fruit fly (PFF), Bactrocera zonata (Saunders) and the Mediterranean fruit fly (MFF), Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) are of the most major pests infesting citrus orchards in Egypt as well as several countries of the world. The present study was carried out to study the seasonal activity of PFF and MFF in navel orange orchards located in Dakahlia governorate, Egypt during two successive fruiting seasons of 2019/2020 and 2020/2021 by using sex attractants and fruit samples. The results obtained showed that, by using sex attractants, PFF males had two peaks each season, whereas MFF showed one to two peaks. By monitoring fruit samples, PFF exhibited one to two peaks of activity seasonally in the non-fallen and fallen fruits; whereas MFF exhibited two to three peaks on the non-fallen and fallen fruits. Both PFF and MFF were more abundant in the fallen fruits than in the non-fallen fruits. The relationships between flies trapped per day (FTD) of PFF and MFF males in Jackson traps and infestation rate of these pests showed that these traps can be used to predict infestation rates of PFF and MFF in their host fruits. Keywords: Bactrocera zonata, Ceratitis capitata, navel orange, Jackson traps, sex attractants