Between June 1980 and October 1981, Aphidius ervi was released at 59 sites throughout the lucerne-growing areas of New South Wales and at 4 sites in southern Queensland as part of a biological control program against Acyrthosiphon kondoi and, more recently, A. pisum . Post-release surveys revealed that A. ervi had become established at of 26 of 29 sites checked in N.S.W. The parasite is now widely dispersed in N.S.W. and Queensland. The hypothesis that the establishment of A. ervi is dependent on the prior presence of A. pisum was not supported by results obtained in this study. Establishment in many areas preceded the arrival of A. pisum . none