g sil b this yields 0 01 wt sil b which is equivalent to the amount contained in the 90 10 blend nonionic trisiloxane alkoxylates have been shown to antagonize the uptake of glyphosate into grasses giving a lower degree of uptake gaskin et al pestic sci 1993 38 185 192 or a lower degree of control then achieved with glyphosate treatments alone the compositions of the present invention provide enhanced glyphosate activity on grasses relative to trisiloxane ethoxylates or glyphosate alone the effect of adjuvant on glyphosate isopropylamine salt gly u2014 ipa efficacy was determined using a barnyardgrass assay barnyardgrass echinochloa crus galli was grown in the lab under fluorescent growth lights and trimmed 11 days after planting from 9 cm to 4 cm when the plants reached to 8 9 cm in height 3 days after trimming they were treated with spray solutions containing either glyphosate alone or with glyphosate gly u2014 ipa at 1 0 0 5 and 0 25 plus a surfactant at 0 1 wt using a spray volume of 96 l ha efficacy was determined by visual observation of plant regrowth 2 weeks after treatment using a rating system were 0 indicates no weed control and 100 indicates complete control table 6 provides the compositions for the various spray mixtures used to treat barnyardgrass in this example table 7 demonstrates that the compositions of the present invention treatments 1 5 provide an overall significant enhancement to glyphosate response relative to glyphosate alone treatment a or to the comparative trisiloxane ethoxylate sil b treatment b barnyardgrass byg.