RELATIVE DRIFT POTENTIAL AND DROPLET SIZE SPECTRA OF AERIALLY APPLIEDPROPANIL FORMULATIONS

Wind tunnel studies were carried out using a Malvern (Malvern Instrume nts, Spring Lane South, Malvern, UK) laser particle size analyser to m easure the droplet size spectra produced by an emulsifiable concentrat e (EC), a water dispersable granule (WDG) and a liquid flowable (LF) f ormulation of Propanil with and without a non-ionic surfactant or a cr op oil. The relative drift potential of each combination of formulatio n and adjuvant was determined in the field by measuring the relative r ecovery on vertical strings, placed 61 m downwind, for formulations sp rayed simultaneously from a Cessna Ag Husky airplane, using a twin-tra cer fluorescent dye technique. Differences were observed in the drople t size spectra and the relative drift potential of the three formulati ons and two adjuvants. Under the conditions of this study, there was a 25% difference in droplet size and a fivefold change in drift potenti al between the formulation types-The EC formulation produced the small est vmd and the greatest amount of drift. (C) 1997 Elsevier Science Lt d.