Residual ducksalad control with florpyrauxifen-benzyl surface-coated urea applications

Abstract Field studies were conducted in 2020 and 2021 at the LSU Agricultural Center H. Rouse Caffey Rice Research Station near Crowley, Louisiana. Studies were performed to evaluate florpyrauxifen-benzyl applied at 0, 7.3, 14.6, 21.9, and 29.2 g ai ha -1 as a surface-coated urea or postflood spray application for residual control of ducksalad. All studies were conducted on a Crowley silt loam (fine smectic, thermic Typic Albaqualfs) with a pH of 6.5 and organic matter content of 2.3%. Plot size consisted of 1.5 by 1.5 m -2 . Each plot consisted of a plastic ring 53 cm in diameter and 30 cm deep. At 70 DAT, ducksalad emergence did not exceed 23% when florpyrauxifen-benzyl was applied via surface-coated urea, compared with 98 to 99% emergence following postflood spray applications. By 56 DAT, over 93% of ducksalad treated with florpyrauxifen-benzyl as a postflood spray, regardless of rate, had reached the petiolate leaf stage. However, ducksalad treated with florpyrauxifen-benzyl as a surface-coated urea application resulted in 3 to 18% petiolate leaf development at 56 DAT. Similar to ducksalad emergence and petiolate leaf development, applying florpyrauxifen-benzyl as a surface-coated urea application reduced ducksalad flowering compared with postflood spray applications. This reduction in flowering throughout the growing season could reduce seed production and potentially impact future ducksalad infestations. Findings suggest florpyrauxifen-benzyl applied via surface-coated urea is more effective at reducing ducksalad emergence, petiolate leaf development, flowering, and fresh weight biomass when compared to postflood spray applications. Overall, applications of florpyrauxifen-benzyl applied via surface-coated urea reach the soil surface rapidly, increasing growth inhibition of ducksalad and possibly other germinating weed species.