In the context of the International Biological Programme, the term biological control is used in its widest sense, to include any method which utilizes particular features of the biology of a pest species in order to limit its numbers, or the damage it causes. United Kingdom work has centred on aphids, a group which includes some of the most important world-wide pests of crops. With one particularly cosmopolitan and dam aging species ( Myzus persicae ) as a model, the aims have been to highlight the problems which are peculiar to aphids and to provide a basis from which to work towards ecologically sound control methods. This paper reviews recent studies in the United Kingdom on four important aspects of aphid biology, namely genetic variation, host plant relations, population dynamics and dispersal by flight, and discusses future strategies for aphid control in the light of this work.