FACTORS AFFECTING FOLIAR RETENTION OF SOME MODEL ADJUVANT OIL-IN-WATER EMULSIONS

The foliar retention of dilute oil-in-water emulsions containing three chemical types of adjuvant oil formulated either as ECs or EWs was co mpared in track-sprayer experiments using the water-soluble tracer, fl uorescein. Although both types of emulsion enhanced tracer deposition onto water-repellant pea and barley foliage, compared with sprays cont aining no adjuvant, consistently better retention was achieved using t he EW emulsions, irrespective of oil composition. On young plants, flu orescein retention using the EC emulsifier alone was similar to that f rom the corresponding emulsions. However, on older plants, retention f rom EC emulsions was superior to that from the EC emulsifier. Comparab le effects were not observed using the EW stabiliser, which had little influence on the efficiency of spray deposition. The retention behavi our of the various oil-based adjuvants is discussed in relation to the ir effects on spray quality and their formulation ingredients. (C) 199 8 Society of Chemical Industry.