ABSTRACT
Deoxyglucose (DOG), a model active ingredient (a.i.), and glyphosate have been used to investigate the effects of surfactants on the kinetics of the foliar uptake process using radiochemical methods. The organosilicone surfactant Silwet® L-77 (0.5%) enabled spray solutions to infiltrate the stomatal pores, providing levels of uptake of 50% into bean, 35% into oat, and 20% into winter wheat within 10 min of application. Silwet L-77 apparently did not enhance subsequent cuticular penetration, but various other surfactants, both organosilicones and “conventionals” (nonorganosilicones), did. The mechanism of nonstomatal enhancement of uptake was more commonly an increased proportion of a.i. ultimately absorbed rather than an increase in the rate of cuticular penetration. The effects of surfactants on uptake were species specific.
