ABSTRACT
In order to study the impact of various adjuvants on the uptake and translocation of aryloxyphenoxypropionate herbicides, high pressure liquid chromatography (HPLC) studies were conducted to compare the metabolic profiles from treated and untreated plant fractions of giant foxtail (Setaria faberi Herrm.) treated with a foliar application of 14C-haloxyfop {2-[4-[[3-chloro-s-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propansic acid}. Similar metabolic profiles were found to exist between the treated leaf tissue and the export fraction.
Experiments were then conducted with various adjuvants being added to the standard formulation. Crop oil concentrate (COC) and crop oil (CO) were more effective in increasing uptake and transport than nonionic wetters. The combination of CO plus wetter resulted in the most efficient level of 14C-uptake and -transport. Subsequent bioassay studies confirmed the benefit of CO-nonionic wetter blends in maximizing herbicidal activity.
The resultant enhanced biological response of the active ingredient permitted the design of formulations containing sufficient volumes of CO and wetter in the formulation concentrate itself, which on dilution with water in the spray tank did not require additional adjuvant. Use of radiotracer techniques are a highly effective means by which to quantitatively select adjuvants, wetters, and their combinations in order to define formulations with maximum performance potential.
