Tetflupyrolimet is the first herbicide with a novel site of action (SOA) labeled PRE and early POST for use in agronomic crops to be labeled in the last three decades. Direct-seeded paddy rice field experiments were conducted near Stuttgart, AR, on a silt loam soil and near Keiser, AR, on a clay soil to evaluate tetflupyrolimet-containing herbicide programs in comparison to commercial standards in conventional, imidazolinone-resistant, and quizalofop-resistant rice systems. Additionally, a furrow-irrigated rice experiment was conducted near Colt, AR, and Keiser to ensure weed control with clomazone and tetflupyrolimet mixtures compared to commercial standards. Twelve commonly planted rice cultivars were also evaluated in response to a single PRE or POST (2- to 3-leaf rice) application of tetflupyrolimet at 200 or 400 g ai ha–1 in a paddy rice system near Colt. When averaged over soil texture and site-year, all herbicide programs provided ≥98% barnyardgrass control at 56 d after (DA) the last application. Visible rice injury varied for each rice system. Still, injury rarely differed among herbicide programs, except at a single evaluation timing in the conventional (7 DA, 3- to 4-leaf applications) and quizalofop-resistant (preflood) systems. All 12 rice cultivars displayed high tolerance to a single PRE or POST application of tetflupyrolimet at 200 or 400 g ai ha–1. No visible injury, stand loss, or negative impact on rice maturity or reduced grain yield was observed for any cultivar. Tetflupyrolimet will be an effective alternative SOA in a program approach for barnyardgrass while maintaining excellent rice crop safety.
Nomenclature: Clomazone; quizalofop; tetflupyrolimet; barnyardgrass; Echinochloa crus-galli (L.) P. Beauv.; rice; Oryza sativa L.
