Evaluation of sulfentrazone and S-metolachlor in brassica vegetables

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.

Automated summary

Small-acreage brassica vegetables require more herbicide options. Limited registered herbicides pose a challenge for niche crops like bok choi and brussels sprouts. The tolerance of different brassica vegetables to S-metolachlor and sulfentrazone was evaluated, and it was found that most seeded brassica vegetables were tolerant of S-metolachlor, while transplanted brassica vegetables were tolerant of both S-metolachlor and sulfentrazone.