Foliar penetration by chemicals

Abstract

Foliar penetration has been investigated by use of fluorescent and radioactive tracers and by a precipitation method. The penetrants tested included both herbicides and nutrients. Cuticular penetration occurred, but, with the exception of P32 phosphate, entry via this route was relatively slow. Stomatal penetration by aqueous solutions occurred rapidly if an efficient surfactant was used at the proper concentration. The concentration of surfactant necessary for stomatal penetration varied with the species being tested. The leaves of Zebrina pendula, Pyrus communis, Prunus armeniaca, and Lactuca scariola were readily penetrated via the stomatal route. Phaseolus vulgaris leaves required a greater concentration of surfactant for stomatal entry, and cuticular penetration through areas over the veins took place quite rapidly.