Field experiments in winter wheat were initiated at two locations in the fall of 2006 and 2007 to evaluate winter annual broadleaf weeds and winter wheat response to POST applications of two saflufenacil formulations applied alone and in combination with 2,4-D amine. Emulsifiable concentrate (EC) and water-dispersible granule (WG) formulations of saflufenacil at 13, 25, and 50 g ai ha−1 were applied with 1.0% (v/v) crop oil concentrate (COC) and mixed with 2,4-D amine at 533 g ae ha−1 without adjuvant. Regardless of rate or formulation, saflufenacil plus COC and saflufenacil plus 2,4-D amine controlled blue mustard ≥ 91% at 17 to 20 d after treatment (DAT) compared with ≤ 50% control with 2,4-D amine alone. At least 25 g ha−1 of saflufenacil EC was necessary to control flixweed > 90%. Excluding COC from saflufenacil plus 2,4-D amine reduced flixweed control from the saflufenacil WG formulation more than the EC formulation. Most saflufenacil treatments did not control henbit satisfactorily (≤ 80%). Wheat foliar necrosis increased with increasing saflufenacil rate to as high as 30% at 3 to 6 DAT, but declined to < 15% at 10 to 20 DAT and was not evident at 30 DAT. Saflufenacil rate, formulation, and mixing with 2,4-D amine also influenced wheat stunting, but to a lesser extent than foliar necrosis. Saflufenacil EC consistently caused greater foliar necrosis and stunting on wheat than saflufenacil WG. Leaf necrosis and stunting were reduced by tank-mixing saflufenacil formulations with 2,4-D amine without COC. Grain yields of most saflufenacil treatments were similar to 2,4-D amine under weedy conditions and herbicide treatments had no effect on grain yield in weed-free experiments. Saflufenacil formulations at 25 to 50 g ha−1 with 2,4-D amine and saflufenacil WG at 25 to 50 g ha−1 with COC can control winter annual broadleaf weeds with minimal injury (< 15%) and no grain yield reductions. The addition of saflufenacil as a POST-applied herbicide would give wheat growers another useful tool to control annual broadleaf weeds, including herbicide-resistant weed species.

Field studies at six locations over 3 yr in Kansas compared pyroxsulam at two application timings to competitive standards for winter annual weed control in winter wheat. Pyroxsulam applied fall-POST (FP) controlled downy brome 84 to 99% and was similar to or greater than sulfosulfuron, propoxycarbazone, or propoxycarbazone plus mesosulfuron. Downy brome control was lower when application timing was delayed until spring (SP), such that no herbicide provided more than 90% downy brome control. Cheat control was 97% or more with almost all herbicides applied FP, and greater than 90% in most locations when herbicides were applied SP. Sulfosulfuron was the exception with only 30 to 81% cheat control. All FP-applied herbicides, except sulfosulfuron at Manhattan, KS, controlled blue mustard 95% or more. Pyroxsulam and propoxycarbazone plus mesosulfuron FP completely controlled henbit at Hesston, KS, in 2009, but no herbicide treatment provided more than 60% control when applied SP. Averaged over application timings, pyroxsulam provided the greatest henbit control (76 and 78%) at Manhattan and Hays, respectively, in 2009, and FP treatments were 33 and 28 percentage points more effective than SP treatments at those locations. Averaged over application timing, wheat yields did not differ between herbicide treatments in five of six locations. Averaged over herbicide treatment, FP-treated wheat yielded more grain than SP-treated wheat at three of the six locations.