Mississippi State University
Poston, Daniel H.
Shaw, David R.
Koger, Clifford H.
Reynolds, Daniel B.
Date of Degree
Graduate Thesis - Open Access
Master of Science
College of Agriculture and Life Sciences
Department of Plant and Soil Sciences
Horseweed has been documented in 70 countries and 40 different crops around the world and is listed as being a problem weed in no-till production systems. Horseweed has developed resistance to many herbicide modes of action including glycine. Field experiments were conducted from 2004 to 2006 in the Mississippi Delta to evaluate the field emergence of horseweed and most effective treatment programs for its control. Field emergence of horseweed was observed occurring primarily in the fall of the year, September through early November, when temperatures were between 15.6 to 23.4 C with later flushes occurring from late January through early April with temperatures ranging from 5.2 to 16 C. Tillage in September followed by herbicide in March gave 100% control of horseweed across all locations. Glyphosate + 2,4-D and glyphosate + dicamba were the best glyphosate-based treatments and provided 90% or better horseweed control 4 WAT both years. Glufosinate-based burndowns provided 81 to 97% horseweed control and soybean yields were generally similar with all glufosinate-based programs.
Eubank, Thomas William, "Field Emergence Of Horseweed [Conyza Canadensis (L.) Cronq.] And Control Utilizing Tillage And Herbicides" (2006). Theses and Dissertations. 2272.