Sulfentrazone crop safety and efficacy in cabbage and broccoli

Abstract

AbstractIn 2021 and 2022, research was initiated at two locations to evaluate the efficacy and safety of sulfentrazone in transplanted cabbage and broccoli. Treatments included oxyfluorfen at 560 g ha−1 applied pretransplant (PRE-T), sulfentrazone applied at 116 or 233 g ha−1 PRE-T, and S-metolachlor applied at 715 g ha−1 immediately after transplanting (POST-T) followed by (fb) oxyfluorfen applied at 210 g ha−1 postemergence (POST) 14 d after planting (DAP). The weedy cover of nontreated 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 the high rate of sulfentrazone reduced total monocotyledonous and dicotyledonous weed densities by 62% and 100%, respectively, relative to the nontreated control. The density of hairy galinsoga (in New Jersey) and combined ladysthumb and prostrate knotweed (in New York) were reduced by 71% to 99%. Except for the low rate of sulfentrazone, all herbicide treatments reduced weed biomass at harvest by ≥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 at both locations. Averaged over treatments, greater stunting was observed in broccoli than in cabbage in New York, whereas stunting estimates were higher for cabbage in New Jersey. All treatments in New Jersey resulted in significantly increased cabbage yield and broccoli and cabbage head sizes relative to the nontreated controls. No yield difference was noted between herbicide treatments and the nontreated check in New York. Data derived from these studies will be used to enhance crop safety recommendations in northeastern U.S. production environments for sulfentrazone used PRE in transplanted cabbage and support a potential label for broccoli.