The very limited Desert Locust infestations of most years since 1963 have been in striking contrast with the massive attacks experienced up to that time, which were clearly (and often admittedly) beyond the control of the organizations concerned in one or more countries in, for example, every one of the 23 years from 1940 to 1962. Attempting to assess possible effects of control measures on the development of the overall Desert Locust situation, relative to those of natural causes, poses formidable problems. However, new control techniques were deployed on unprecedented scales in particular series of locust campaigns during the early 1960s. Detailed monitoring and mapping of the overall Desert Locust situation provided circumstantial evidence of the probable impace of these campaigns. Further circumstantial evidence of the effects of these developments in methods and organization was provided by the short-lived locust upsurges of 1964 and 1967-8.