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Absorption and translocation of glyphosate with conventional and organosilicone adjuvants


* Megh Singh, IFAS, University of Florida, Citrus Research and Education Center, 700 Experiment Station Rd, Lake Alfred, FL 33850, USA.


This study was conducted to determine the effects of three organosilicone-based and six conventional organic adjuvants on the absorption and translocation of 14C-glyphosate in guineagrass and redroot pigweed. The organosilicone adjuvants produced rapid absorption of the 14C-glyphosate into the redroot pigweed leaves, reaching maximum absorption within 0.5–1.0 h after application. The conventional adjuvants produced slower absorption of the 14C-glyphosate, as the maximum absorption was not achieved until at least 24 h after application in redroot pigweed, remaining similar until 72 h. In guineagrass, the maximum absorption of the glyphosate was earlier than 24 h with the organosilicone-based adjuvants, compared with longer times for the conventional adjuvants. The organosilicone-based adjuvants also increased the glyphosate translocation in redroot pigweed, but not in guineagrass. Organosilicone adjuvants have the potential to provide greater rainfastness to glyphosate on redroot pigweed and, to a lesser extent, on guineagrass.