The seasonal occurrence ofPhyllonorycter elmaellaDoganlar&Mutuura, a tentiform leafminer, and its parasitoid,Pnigalio flavipes(Ashmead), in insecticide-free blocks located in commercial apple orchards was determined.P. elmaellahad three complete generations each year; population densities increased in each generation.P. elmaellasap feeders (first to third instars) were “abnormally” abundant in the blocks at the end of each season, possibly because of a delay in their development.P. flavipeshad at least the same number of generations asP. elmaella. Parasitoid activity decreased as the season progressed. Phenology data showed adultP. flavipesemerged almost concurrently with adultP. elmaelladuring the spring and summer generations, 2–3 wk before tissue feeders (fourth and fifth instars), were present in the orchard. This emergence pattern may be caused by a reproductive advantage for femaleP. flavipesto feed on sap feeders before oviposition. The number of individuals ofP. elmaellathat are able to overwinter successfully, rather than the seasonal levels of parasitism, seems to determine the leafminer's year-to-year population dynamics. However, parasitoid activity reduced the leafminer's intraseasonal population increase and kept its densities below treatment threshold levels in all orchard blocks examined.