Cabbage seed germination for the assessment of adjuvant effects on 2, 4-D iso-octyl ester volatility

Abstract

The germination rate of cabbage seeds (Brassica oleracea cv. Hercules) exposed to the vapour of the 2,4-dichlorophenoxy iso-octyl ester (2,4-D IOE) was used in a bioassay to determine the effectiveness of commercial adjuvants in reducing the volatility of this hormonal herbicide. The herbicide vapour was generated by a source of known concentration placed on filter paper at the bottom of a closed system. The phytotoxicity of vapours released by the adjuvants was tested in the same manner. Of the six adjuvants tested, (Agripon Super®, Armoblen T600®, Bladbuff 5®, Getdown®, Derimin® and Surfynol®), Surfynol was found to generate phytotoxic vapours which reduced the germination rate of seeds. Although the adjuvants did not reduce the volatility of 2,4-D IOE in the described system, they were found to be effective if filter paper was omitted from the source solution. This reduction was not sufficiently dramatic to warrant the use of these substances for reducing the volatility of hormonal herbicides in agricultural practices.