1 April 2018 Evaluation of Florpyrauxifen-Benzyl on Herbicide-Resistant and Herbicide-Susceptible Barnyardgrass Accessions
M. Ryan Miller, Jason K. Norsworthy, Robert C. Scott
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Florpyrauxifen-benzyl is a new herbicide under development in rice that will provide an alternative mode of action to control barnyardgrass. Multiple greenhouse experiments evaluated florpyrauxifen-benzyl efficacy on barnyardgrass accessions collected in rice fields across Arkansas, and to evaluate its efficacy on herbicide-resistant biotypes. In one experiment, florpyrauxifen-benzyl was applied at the labeled rate of 30 g ai ha-1 to 152 barnyardgrass accessions collected from 21 Arkansas counties. Florpyrauxifen-benzyl at 30 g ai ha-1 effectively controlled barnyardgrass and subsequently reduced plant height and aboveground biomass. In a dose-response experiment, susceptible-, acetolactate synthase (ALS)-, propanil-, and quinclorac-resistant barnyardgrass biotypes were subjected to nine rates of florpyrauxifen-benzyl ranging from 0 to 120 g ai ha-1. The effective dose required to provide 90% control, plant height reduction, and biomass reduction of the susceptible and resistant biotypes fell below the anticipated labeled rate of 30 g ai ha-1. Based on these results, quinclorac-resistant barnyardgrass as well as other resistant biotypes can be controlled with florpyrauxifen-benzyl at 30 g ai ha-1. Overall, results from these studies indicate that florpyrauxifen-benzyl can be an effective tool for controlling susceptible and currently existing herbicide-resistant barnyardgrass biotypes in rice. Additionally, the unique auxin chemistry of florpyrauxifen-benzyl will introduce an alternative mechanism of action in rice weed control thus acting as an herbicide-resistance management tool.

Nomenclature: Florpyrauxifen-benzyl; barnyardgrass, Echinochloa crus-galli (L.) Beauv.; rice, Oryza sativa L.

© Weed Science Society of America, 2017.
M. Ryan Miller, Jason K. Norsworthy, and Robert C. Scott "Evaluation of Florpyrauxifen-Benzyl on Herbicide-Resistant and Herbicide-Susceptible Barnyardgrass Accessions," Weed Technology 32(2), 126-134, (1 April 2018). https://doi.org/10.1017/wet.2017.100
Received: 21 August 2017; Accepted: 2 October 2017; Published: 1 April 2018
Dose response
Herbicide resistance
Rinskor™ active
weed control
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