Project Details:

Title:
Integrated Strategies to Manage Herbicide Resistant Weeds in MD Soybean Systems

Parent Project: This is the first year of this project.
Checkoff Organization:Maryland Soybean Board
Categories:Weed control
Organization Project Code:
Project Year:2017
Lead Principal Investigator:Benjamin Beale (University of Maryland)
Co-Principal Investigators:
Keywords: Herbicide Resistance, marestail, Palmer Amaranth, ragweed, Weed Control

Contributing Organizations

Funding Institutions

Information and Results

Comprehensive project details are posted online for three-years only, and final reports indefinitely. For more information on this project please contact this state soybean organization.

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Final Project Results

Updated June 16, 2020:
Herbicide treatments
Results from the 2017 trial are consistent with findings in 2015 and 2016. The trials indicate significantly better control of Palmer amaranth with the use of any residual product when compared to a non-treated control. Prowl, Dimetric, and Prowl plus Dimetric provided 1-2 weeks of control, Boundary and Canopy provided 2-3 weeks of control and Fierce, Fierce XLT, Authority XL, and BroadAxe XC provided 3-5 weeks of control. The trial did not show significant differences between treatments that received an additional post-emergence application of the residual herbicide Dual. The use of residual products also provided a longer timeframe for the timely and thus effective application of post-emergent herbicides. The trials show that a post-emergent herbicide treatment needs to be applied within 28 days of planting to achieve reliable control. Waiting beyond 28 days will result in emerged Palmer amaranth plants that are larger than the 3-4 inch height limit for post-emergent herbicides. If no residual herbicide is used, the post-emergent treatments need to be applied within 14 days, and season long control is very unlikely.

Ragweed trials
The trial indicates significantly better control of common ragweed with the use of any residual product when compared to a non-treated control. Treatments that utilized more than one effective mode of action provided better control then single mode of action treatments. Products containing the active ingredients linuron, metribuzin, and flumioxazin performed best. Command (clomazone) performed significantly better than the control, but was not as effective as other products. There was some plant stunting and phytotoxicity observed on plots treated with Linex plus Dimetric.

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Results indicate significantly better control of Palmer amaranth with the use of any residual product when compared to a non-treated field. The length of control provided by residual products varied from two to six weeks. Products with the active ingredient flumioxazin including premixes of Fierce or Fierce XLT or products with the active ingredient sulfentrazone including premixes such as Broadaxe or Authority XL provided the most consistent control. Residual herbicides also resulted in differences in weed height over the length of the season. This is especially advantageous in that it provides a longer timeframe for the timely and thus effective application of post-emergent herbicides.

Project Years