We investigated whether preplant root dips or postplant sprays or drenches could be used to control the black peach aphid, Brachycaudus persicae (Passerini), on young peach trees. In greenhouse trials, B. persicae died after being placed on peach trees that had their roots dipped in imidacloprid before planting. All rates (0.8, 1.6, and 3.2 ml/liter of water) tested controlled this aphid. B. persicae died faster on trees dipped in imidacloprid (1.6 ml/liter of water) for 5 min before planting than on trees dipped for 2 s. Aphids eventually died on all treated trees. Approximately 50% of untreated trees died from B. persicae infestations in greenhouse studies. Results from a field experiment show that peach trees root-dipped in imidacloprid before planting or drenched with imidacloprid after planting eliminate B. persicae infestations and prevent root colonization for at least 1 yr.