Trifloxysulfuron (CGA-362622) at 2.5, 5 and 10 g a. i./ha mixed with non-ionic (0.25% Induce and X-77), organosilicone (0.1% Kinetic and Silwet L-77) and crop oil concentrate (1.0 % Agridex and Meth-N-Oil) adjuvants was evaluated for bioefficacy, surface tension, contact angle and chlorophyll fluorescence responses in guineagrass (Panicum maximum L.), sicklepod (Senna obtusifolia L.), yellow nutsedge (Cyperus esculentus L.) and cotton (Gossypium hirsutum L.). The lowest surface tension and contact angle were recorded with L-77 mixed with trifloxysulfuron. Among the six adjuvants, surface tension and contact angle were highest with Meth-N-Oil; however, these differences did not greatly influence herbicide efficacy. Decreasing or increasing the adjuvant concentrations from 1X to 0.5 or 4X with 10 g/ha trifloxysulfuron had only 2 to 4% variations in surface tension and contact angle compared to recommended rates (X) when data were averaged over adjuvants and concentrations. Adjuvants had no antagonistic effects for trifloxysulfuron activity on any weed species. Phytotoxicity symptoms of trifloxysulfuron on cotton disappeared after two weeks, but plant height and fresh weight were reduced 3 WAT compared to control plants. Reduction in plant height or fresh weight of cotton was similar for different adjuvants mixed with trifloxysulfuron. Guineagrass was less affected by trifloxysulfuron plus adjuvants than yellow nutsedge or sicklepod. Kinetic mixed with trifloxysulfuron was more effective in reducing plant height and fresh weight of guineagrass compared to other adjuvants; however, activities were comparable when data averaged over species and rates for different adjuvants. Chlorophyll fluorescence was reduced in all the species after herbicide application, but the reduction was not consistent with application rates, species and duration of 1, 4, 7 and 14 days after treatment (DAT). Reduction in chlorophyll fluorescence in treated plants of cotton was less than weeds, but followed no particular trend with herbicide rates or adjuvant interaction. Visual mortality of 17, 53 and 36% at 2 WAT in guineagrass, sicklepod and yellow nutsedge, respectively, was not visible in similar reduction in chlorophyll fluorescence, when data were averaged over treatments. Chlorophyll fluorescence may not be an ideal tool to predict herbicidal efficacy of trifloxysulfuron in the test species.