Mississippi State University
McCurdy, James D.
Tseng, Te-ming P.
Stewart, Barry R.
Date of Degree
Graduate Thesis - Open Access
Plant and Soil Sciences
Master of Science (M.S.)
College of Agriculture and Life Sciences
Department of Plant and Soil Sciences
Quinclorac controls crabgrass (Digitaria spp.) post-emergence in cool- and warm-season turfgrass. A rate response study revealed that two Mississippi smooth crabgrass (Digitaria ischaemum) species (MSU1 and MSU2) are resistant to quinclorac. Following that, field experiments were carried out to evaluate programmatic approaches to control one of these populations. Despite prior study on quinclorac-resistant weeds, to date, quinclorac-resistant smooth crabgrass and its mechanism of resistance have only been reported once in California. The mechanism of resistance of MSU1 and MSU2 relative to susceptible (SMT) was then investigated. The SMT biotype accumulated three times more cyanide than the resistant populations. Glutathione-S-transferase (GST) activity was evaluated as a possible contributor to non-target site resistance. The GST activity was elevated in the MSU1 and MSU2 populations. These findings suggest a non-target site–based mechanism of resistance involving the accumulation of cyanide. Further research is needed to investigate potential target-site mechanisms of resistance.
Putri, Atikah Dwi, "Characterizing quinclorac-resistant smooth crabgrass (Digitaria ischaemum) control and possible metabolic mechanisms of resistance" (2023). Theses and Dissertations. 5751.
Available for download on Thursday, May 15, 2025