Population fluctuations of blackmargined aphid, Monellia caryella (Fitch) (Aphididae, Hemiptera) and its predators and parasitoids were identified in an unmanaged pecan orchard in Sultanhisar district of Aydin Province. Aphids on fifty compound leaves were counted weekly between April and December. Nymphs and adults of the blackmargined aphid overwintering on pecan branches as egg were seen between the December-April. Two peaks took place in population in both years (2008, 2009) including the second half of May and in October. In research, fifteen predators, three parasitoids of M. caryella and two hyperparasites species were obtained. It was determined that there were numerous predators, and few in number of parasitoids. Coccinellidae and Chrysopidae families were reported as the most abundant predator groups. Chrysopid population was higher than coccinellid population. Adalia decempunctata (L.) and Chrysopa viridana (Schneider) were prominent species. Coccinellid population in spring and chrysopid population in summer and fall were higher. The percent parasitism by Aphelinus sp. (Hym.; Eulophidae), Aphidius matricariae Haliday and Trioxys pallidus (Haliday) (Hym.; Braconidae) was 0.85% in 2008 and 0.17% in 2009.