Effect of Tank-Mix Adjuvant on the Behavior of Chlorantraniliprole and Difenoconazole in Soil

In this study, we performed both laboratory and field studies to analyze the behavior of the pesticides chlorantraniliprole (CAP) and difenoconazole (DIF) by the presence of tank adjuvant in soil. In the laboratory, DIF exhibited a significantly higher Freundlich maximum adsorption capacity than CAP, which is consistent with the higher octanol–water partition coefficient of DIF. The sorption of CAP and DIF under laboratory conditions was significantly increased by the presence of adjuvant, which was confirmed by the soil contact angles. Soils that contained more aromatic components were able to support greater sorption of pesticides. The half-lives of CAP and DIF tested in fluvo-aquic soil under field conditions were slightly reduced by the adjuvant. The Groundwater Ubiquity Score (GUS) of CAP suspension concentration applied alone and with adjuvant was 1.39 and 1.33, respectively, whereas the GUS of DIF suspension concentrate applied alone and with adjuvant was 0.38 and 0.18, respectively. Thus, the adjuvant reduced the GUS indices of CAP and DIF, thereby reducing their potential to leach into groundwater