Small-acreage brassica vegetables need additional herbicide options. Among the vegetables grown in California are a number of niche crops, such as bok choi and brussels sprouts, that have a limited number of registered herbicides, such as DCPA. Sulfentrazone and S-metolachlor have food use tolerances for use on brassica head and stem Group 5-16, which includes crops like bok choi and brussels sprouts, as well as brassica leafy greens Subgroup 4-16B, which includes crops like kale. However, there is a lack of data for S-metolachlor and sulfentrazone on a wide variety of seeded and transplanted brassica vegetables. S-metolachlor applied preemergence (PRE) was evaluated on six direct-seeded brassica vegetables during 2019 and 2020, including bok choi, broccoli rabe, collard, mizuna, radish, and mustard greens. S-metolachlor and sulfentrazone were both evaluated PRE in transplanted brussels sprouts and kale. The results indicate that most of the seeded brassica vegetables were tolerant of S-metolachlor and that transplanted brassica vegetables were tolerant of both S-metolachlor and sulfentrazone. Broccoli rabe was moderately injured in 2020, but yields did not vary among treatments either year.

Nomenclature: DCPA; sulfentrazone; S-metolachlor; bok choi, Brassica rapa L. subsp. Chinensis (Rupr.) Olsson; broccoli rabe, Brassica rapa L. var. rapa brussels sprouts, Brassica oleracea L. var. gemmifera DC.; collard, Brassica oleracea L. var. acephala DC.; mizuna, Brassica rapa L. subsp. japonica; kale, Brassica oleracea L. var. sabellica L.; mustard greens, Brassica juncea (L.) Czern.; radish, Raphanus sativus L.