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Bryan P. Reeb MS Thesis.pdf (243.6 KB)

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A Systems Approach to Conyza canadensis Management

Reeb, Bryan P, Reeb
http://rave.ohiolink.edu/etdc/view?acc_num=osu1523880629100269

Abstract Details

2018, Master of Science, Ohio State University, Horticulture and Crop Science.
In Ohio, no-tillage soybean production, glyphosate, and acetolactate synthase inhibitor (ALS)-inhibiting herbicides are common components for management of horseweed. However, resistance to glyphosate was confirmed in Ohio in 2002, followed by multiple resistance to both ALS inhibitors and glyphosate in 2003. Field studies were conducted from the fall of 2009 through the summer of 2016 to develop strategies for management of horseweed populations with these types of resistance in no-tillage soybeans. The objectives were to: 1) determine the efficacy of fall-applied herbicides for management of horseweed emerging in the spring; 2) determine the effect of spring application timing and herbicide on the residual control of horseweed through mid-summer; and 3) determine the most effective herbicide program for soybeans resistant to glufosinate, glyphosate/dicamba, or to glyphosate/glufosinate/2,4-D. Among the fall-applied herbicides, only chlorimuron and flumioxazin have potential to control spring-emerging horseweed when applied the previous fall. Chlorimuron controlled ALS-sensitive horseweed only, and flumioxazin provided control into spring only at one site. Overall, this study showed low and variable potential for fall herbicide treatments to provide control of spring-emerging horseweed that are resistant to ALS inhibitors. Spring preplant application of a single active ingredient did occasionally provide effective residual control of horseweed through the time of a POST application, but this occurred most consistently with sequential preplant applications or multiple-herbicide treatments. Combinations of metribuzin and either flumioxazin, saflufenacil, or sulfentrazone were needed to provide 90% or greater control through soybean harvest. The results from these studies show that horseweed populations can be controlled using residual herbicides exclusively, applied either in the fall or in spring prior to planting. However, there was considerable variability in effectiveness among herbicides and environments, and differences among herbicides were not consistent among studies. Studies with glufosinate-resistant soybeans showed the effectiveness of several approaches. Failure to use fall herbicide treatments or spring herbicides with residual activity on horseweed can result in inadequate late-season control, even where it is possible to use glufosinate POST. The ability to use 2,4-D more intensively in a 2,4-D-resistant soybean can result in effective late-season control of glyphosate-resistant horseweed. For a number of the treatments that relied primarily on 2,4-D for control of emerged plants though, effective control required both at plant and POST applications of 2,4-D. The inclusion of other effective herbicides, such as paraquat or saflufenacil, in the spring treatment, or glufosinate in the POST, can improve control and reduce reliance on 2,4-D. Dicamba was more effective than 2,4-D on emerged horseweed, especially in the absence of fall-applied herbicides. Dicamba herbicide systems adequately controlled horseweed if dicamba was included in the POST, or if used exclusively in the preplant application in combination with effective residual herbicides.
Mark Loux (Advisor)
Kent Harrison (Committee Member)
Laura Lindsey (Committee Member)
66 p.
Agriculture

Recommended Citations

Citations

  • Reeb, Reeb, B. P. (2018). A Systems Approach to Conyza canadensis Management [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523880629100269

    APA Style (7th edition)

  • Reeb, Reeb, Bryan. A Systems Approach to Conyza canadensis Management. 2018. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1523880629100269.

    MLA Style (8th edition)

  • Reeb, Reeb, Bryan. "A Systems Approach to Conyza canadensis Management." Master's thesis, Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523880629100269

    Chicago Manual of Style (17th edition)

osu1523880629100269
294
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