Mississippi State University
Shaw, David R.
Byrd, John D.
Massey, Joseph H.
Koger, Clifford H.
Date of Degree
Graduate Thesis - Open Access
Master of Science (M.S.)
College of Agriculture and Life Sciences
Department of Plant and Soil Sciences
In field efficacy trials most glyphosate/surfactant combinations tested control barnyardgrass as well as preormulated glyphosate products 21 days after treatment (DAT). Preormulated glyphosate products controlled barnyardgrass quicker than combination treatments, most likely due to improved glyphosate formulations with improved surfactant systems. In greenhouse trials, preormulated glyphosate products exhibited greater fresh weight reductions across all species tested, including barnyardgrass, broadleaf signalgrass, hemp sesbania, johnsongrass, large crabgrass, pitted morningglory, prickly sida, sicklepod, yellow foxtail and Palmer amaranth. Nonionic tallow amine treatments exhibited variable control among species. A shikimate analysis was developed using non-glyphosate-tolerant soybean to estimate efficacy of surfactants; data were then correlated to the visual efficacy data on barnyardgrass in the field. However, there was not sufficient variability in barnyardgrass control to use the shikimate analysis as a predictor.
Massey, Cody Alan, "Development of a High throughput Surfactant Screening Procedure using Shikimic Acid Analysis" (2012). Theses and Dissertations. 1412.