Aerial application

[Introduction]: At the beginning of the 1980s it was estimated that there were approximately 26,000 aircraft worldwide involved with the application of pesticides, with the numbers roughly equally divided between the United States of America, the USSR, and the rest of the world (1). This figure has probably decreased in recent years, primarily due to the decline in communal farming in the USSR and Eastern Europe, but also due to improvements in ground application equipment and public concern over spray drift in some European countries. However, aircraft are still used extensively in public health and are still required for the economic production of many crops such as cotton, rice, fruit and vegetables, sugar cane, and forestry. In 1998 there were 2600 registered aerial operators in the United States of America with approximately 6000 aircraft. According to recent United States Department of Agriculture figures, out of 125 million hectares harvested in the United States in 1998, approximately 25% of the land area receiving crop protection products was sprayed using aircraft. The use of aircraft as a means of agrochemical application has developed due to the greater speed, better timing, and efficiency of application offered by an airborne platform. Aircraft are able to apply agricultural products rapidly over large areas within narrow optimum application windows, often essential for control of the pest. Aircraft can be used over impenetrable canopies and wet! irrigated areas, and problems of soil compaction disease spread associated with ground vehicles are entirely avoided. However, disadvantages include the high risk of flying close to the ground and the fact that aircraft (especially fixed wing) attract attention to the process of pesticide application and cause public concern. Aircraft also release spray at greater height and speed, which may increase drift compared to ground-based equipment