In 1966, 1967, and 1968 natural enemies rather than insecticides were the only means of control for 3 damaging species of aphids in a 10-acre apple orchard. The more important natural enemies of the rosy apple aphid, Dysaphis plantaginea (Passerini), the apple aphid, Aphis pomi De Geer, and the woolly apple aphid, Eriosoma lanigerum (Hausmann) were identified and evaluated. Natural enemies did not prevent damage by rosy apple aphids in 1967, or extensive leaf curl by A. pomi in 1968. Woolly apple aphids became numerous in 1967, and were reduced somewhat but not controlled satisfactorily in 1968. Because of possible long term debilitating effect by apple and woolly aphids, and the unreliability of natural control of rosy apple aphids, chemical control of aphids seems to be advisable as part of an integrated control program of apple pests. Ryania showed promise in prebloom sprays for control of rosy apple aphids. Azinphosmethyl was destructive to the major aphid enemies, but ryania and lead arsenate were harmless.