These guidelines were prepared by Hans Dobson of the Natural Resources Institute, UK, based at the International Pesticide Application Research Centre (IPARC), Imperial College London. Valuable assistance was provided by Mamoon Al Alawi of the Desert Locust Unit, Sultanate of Oman and Mohammed Ishfaque of the Department of Plant Protection and Quarantine, Pakistan. The guidelines are based on the format and content of a series of other FAO sprayer guidelines developed by T. L. Wiles and D. G. Sharp, of T L Wiles and Associates Limited, Chichester, UK with the assistance of Professor G. A. Matthews, IPARC, Imperial College London. The design and performance requirements were also informed by the findings of two FAO workshops (FAO, 1994 and FAO, 2002), which evaluated Desert Locust spraying equipment. The valuable contributions and comments of many international specialists from both the public and private sectors are also gratefully acknowledged.