Effects of the agrochemical products and adjuvants on spray quality and drift potential
Effets des produits phytosanitaires et des adjuvants sur la qualité de la pulvérisation et la dérive
Résumé
Recently, the Cemagref has applied a protocol to measure, in laboratory, the effects of the pesticides and adjuvants on the spray quality and drift potential. It has used a Dantec Phase Doppler Anemometer to measure the droplet size of airborne spray and a wind tunnel to evaluate the drift potential. Four mixtures were tested: i) water, ii) water plus glyphosate (4%), iii) water plus glyphosate (4%) plus the adjuvant advised in France for this herbicide noted X in this work (0.5%) and iv) water plus glyphosate (4%) plus LI 700 (0.5%). Measurements show that agrochemical products and adjuvants do not extensively modify the number of large droplets but their essential action is on smaller droplets. So, it is possible to reduce drift without deteriorating spray quality. The reduction of the drift is also obtained by shifting the droplet spectrum by using the Turbo Teejet nozzle. This nozzle reduces the number of fine and very fine droplets and, increases the number of coarse droplets augmenting the run off risks. The wind tunnel measurements have demonstrated that the action of agrochemical products and adjuvants on the drift potential is more important than those of pressure.