WIND TUNNEL TESTS WITH DIFFERENT TRACERS AND COLLECTION TECHNIQUES FOR THE MEASUREMENT OF SPRAY DRIFT Eva Brusselman *1 eva.brusselman@UGent.be, David Nuyttens 2 , Katrijn Baetens 3 , Donald Gabriels 4 , Wim Cornelis 4 , Koen Van Driessen 1 , Walter Steurbaut 1 1 Department of Crop Protection Chemistry, University Ghent, Coupure links 653, 9000 Ghent, Belgium 2 Ministry of the Flemish Community, Agricultural Research Centre, Department of Mechanisation, Labour, Buildings, Animal Welfare and Environmental Protection (CLO-DVL), Burg. Van Gansberghelaan 115, 9820 Merelbeke, Belgium 3 Department of Agro-Engineering and Economics, Catholic University of Leuven, De Croylaan 42, 3001 Leuven, Belgium 4 Department of Soil Management and Soil Care, University Ghent, Coupure links 653, 9000 Ghent, Belgium Abstract - In the history of pesticide drift-measuring techniques, different tracers and collection techniques have been used. At the start of a new Flemish IWT project ‘Protecting the Flemish environment against drift - The importance of drift-reducing techniques’, wind tunnel tests have been performed to select the most efficient tracer and collection technique. The most important objective of this study was to investigate the effect of a certain combination of collection and tracer techniques on the measured drift quantities. As tracer types a fluorescent tracer (Renaissance W15), two different mineral chelates (cobalt and molybdenum), a NaCl-solution and a fungicide (Tolylfluanide) were used. Two different collection techniques were tested: ditches incorporated in the wind tunnel floor with filter paper and with filtering cloths. The recovery of the different tracers combined with the two collection materials was calculated. The advantages and disadvantages of the tracers and collection materials are enumerated in this article. Keywords drift, wind tunnel, tracer, collection material Introduction and objectives At the start of a new Flemish IWT project ‘Protecting the Flemish environment against drift – The importance of drift-reducing techniques’, wind tunnel and field measurements of drift are planned. Several tracers and collection materials can be used to quantify drift in the field or in a wind tunnel. In this research, experiments were performed to obtain a better understanding of the importance of tracer and collector types in wind tunnel measurements of droplet deposition. The most common collector types in drift research (filter paper and filtering cloths) were combined in these tests with four different tracer types (a fluorochrome, a salt, two mineral chelates and a fungicide). Deposition results were calculated and compared. * Laboratory of Crop Protection Chemistry, Coupure links 653, 9000 Ghent (Belgium)