Growth chamber experiments were conducted in the fall of 2006 and spring of 2007 to determine winter wheat, flixweed, and henbit response to POST treatments of saflufenacil at 13, 25, and 50 g ai ha−1 applied alone and in combinations with bentazon at 560 g ai ha−1 or 2,4-D amine at 533 g ae ha−1 and nonionic surfactant (NIS) at 0.25% v/v. Mixtures of saflufenacil and 2,4-D amine were also applied without NIS. Necrosis was observed on wheat leaves within 1 d after treatment (DAT) and peaked at 5 to 7 DAT. Saflufenacil at 13, 25, or 50 g ai ha−1 applied alone or in combination with 533 g ae ha−1 of 2,4-D amine plus NIS caused 19 to 38% (alone) and 24 to 40% (in combination) wheat foliar necrosis, respectively. Foliar necrosis of wheat was 14% or less when saflufenacil, at any rate, was mixed with bentazon or 2,4-D amine without NIS. Combinations of saflufenacil at any of the rates tested plus bentazon and NIS did not reduce wheat dry weight. Saflufenacil plus 2,4-D amine without adjuvant resulted in similar wheat dry weights as 2,4-D amine. Saflufenacil plus 2,4-D amine without NIS provided 99% control of flixweed at 21 DAT, but henbit control ranged from 81 to 88%. In comparison, saflufenacil at 50 g ha−1 mixed with bentazon and NIS controlled flixweed at 92% and henbit at 63% at 21 DAT. This research indicates saflufenacil has potential for POST use in winter wheat to control winter annual broadleaf weeds when tank-mixed with 2,4-D amine without NIS, but additional research is needed to discover ways to improve crop safety without reducing weed control.
Nomenclature: 2,4-D amine; bentazon; saflufenacil; flixweed, Descurainia sophia L. Webb. ex Prantl DESSO; henbit, Lamium amplexicaule L. LAMAM; winter wheat, Triticum aestivum L. ‘KS03HW6-1’.