Sulfentrazone Crop Safety and Efficacy in Cabbage and Broccoli

Abstract

Abstract In 2021 and 2022, research was initiated to evaluate the efficacy and safety of sulfentrazone in transplanted cabbage and broccoli. Treatments included oxyfluorfen at 560 g ha -1 pre-transplant (PRE-T), sulfentrazone at 116 or 233 g ha -1 PRE-T, and S -metolachlor at 715 g ha -1 immediately applied after transplanting (POST-T) followed by (fb) oxyfluorfen at 210 g ha -1 postemergence (POST) 14 d after planting (DAP). Concerning weed cover, the weedy non-treated plots averaged between 6% (14 DAP) and 72% (42 DAP); all herbicide-treated plots averaged less than 30% cover at 42 DAP. At 14 and 28 DAP, oxyfluorfen, S –metolachlor fb oxyfluorfen, and sulfentrazone high rate reduced total monocotyledonous and dicotyledonous weed densities 62 and 100% relative to the non-treated control. Hairy galinsoga (NJ) and combined ladysthumb and prostrate knotweed (NY) density was reduced 71 to 99%. Except for the low rate of sulfentrazone, all herbicide treatments reduced weed biomass at harvest ≥ 88%. Crop injury varied in response to herbicide treatments or weed competition but was also affected by crop and location. Between 14 and 28 DAP, the greatest amount of stunting (22%) was noted in the S -metolachlor fb oxyfluorfen treatments for both locations. Averaged over treatments, greater stunting was observed in broccoli as compared to cabbage in NY, whereas stunting estimates were higher for cabbage in NJ. All NJ treatments significantly increased cabbage yield and broccoli and cabbage head sizes relative to the non-treated control. No yield difference was noted between herbicide treatments and the non-treated check in NY. Data derived from these studies will be used to enhance crop safety recommendations in Northeast production environments for sulfentrazone used PRE in transplanted cabbage and support a potential label for broccoli.