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ARS Home » Southeast Area » Stoneville, Mississippi » Sustainable Water Management Research » Research » Publications at this Location » Publication #427948
Research Project: Development of Best Management Practices, Tools, and Technologies to Optimize Water Use Efficiency and Improve Water Distribution in the Lower Mississippi River Basin

Location: Sustainable Water Management Research

Title: Barnyardgrass (Echinochloa crus-galli) control and rice injury with labeled herbicides following exposure to sublethal concentrations of paraquat

Author
item SANDERS, TAMEKA - Mississippi State University
item BOND, JASON - Mississippi State University
item ALLEN, TOM - Mississippi State University
item GHOLSON, DREW - Mississippi State University
item KRUTZ, L. JASON - Mississippi State University
item WEBSTER, ERIC - University Of Wyoming

Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/8/2024
Publication Date: 2/12/2024
Citation: Sanders, T.L., Bond, J.A., Allen, T.W., Gholson, D., Krutz, L., Webster, E.P. 2024. Barnyardgrass (Echinochloa crus-galli) control and rice injury with labeled herbicides following exposure to sublethal concentrations of paraquat. Weed Technology. 38/71-89. https://doi.org/10.1017/wet.2024.8.
DOI: https://doi.org/10.1017/wet.2024.8

Interpretive Summary: In Mississippi, rice crops can be affected by paraquat-based herbicides used on neighboring fields of corn, cotton, and soybeans. When rice plants are exposed to a lower-than-lethal dose of paraquat, farmers still need to manage weeds effectively. From 2019 to 2021, research was conducted to see how different herbicides affected rice plants and their ability to control barnyardgrass after this exposure. The study tested several herbicides, including imazethapyr and florpyrauxifen-benzyl, and found that rice showed some injury after treatment, particularly from florpyrauxifen-benzyl. However, all herbicides helped control barnyardgrass effectively compared to not using any herbicide at all. Overall, the research concluded that while there may be some injury to rice, using labeled herbicides after paraquat exposure can still lead to significant weed control, and the choice of herbicide should depend on the specific weeds that need to be managed.

Technical Abstract: Rice in Mississippi is often in early seedling growth stages when paraquat-based herbicide treatments are commonly applied to corn, cotton, and soybean; therefore, off-target movement of the herbicide onto adjacent rice fields may occur. After an off-target movement event has occurred, weed management in the rice crop is still necessary. Field studies were conducted from 2019 to 2021 in Stoneville, MS, to evaluate rice injury and barnyardgrass control with labeled herbicides after exposure to a sublethal concentration of paraquat. Herbicide treatments were label-recommended rates of imazethapyr, quinclorac, propanil, bispyribac-sodium, cyhalopfop, and florpyrauxifen-benzyl applied following rice exposure to a sublethal concentration of paraquat. Rice injury was detected 7 and 28 d after treatment (DAT) and was =35% and =14%, respectively, for all herbicides. Florpyrauxifen-benzyl and imazethapyr caused the greatest rice injury at 28 DAT. Following paraquat exposure, barnyardgrass control was similar for all labeled herbicide treatments at 7, 14, and 28 DAT except for florpyrauxifen-benzyl and no herbicide (paraquat alone) at 7 DAT. Across all evaluations, barnyardgrass control was at least 12% greater following paraquat exposure and labeled herbicide treatments than with no paraquat exposure. The current research demonstrates that labeled rates of herbicides applied following exposure to a sublethal concentration of paraquat resulted in <36% injury and provided as great as 95% control of barnyardgrass, depending on the herbicide treatment. Therefore, the labeled herbicides choice following rice exposure to a sublethal concentration of paraquat should be based on weed spectrum.