Broadleaf Weed Control and Cabbage Seed Yield following Herbicide Application

Abstract

Broadleaf weed control with trifluralin, oxyfluorfen, pendimethalin, clopyralid, pyridate, and metolachlor in cabbage ( Brassica oleracea L.) grown for seed was evaluated. No single herbicide controlled broadleaf weeds adequately, with the exception of pendimethalin at 1.92 and 3.84 kg a.i./ha. However, combinations of trifluralin + oxyfluorfen, pendimethalin + clopyralid, and oxyfluorfen + pyridate effectively controlled weeds and did not reduce seed yields. Herbicides caused slight to moderate injury symptoms to cabbage plants, with the greatest injury caused by pendimethalin and the least by trifluralin and metolachlor. However, plants recovered from these symptoms and appeared normal at the bud stage. None of the herbicides applied alone or in combinations adversely affected cabbage population, height, or flowering date. Chemical names used: 3,6-dichloro-2-pyridinecarboxylic acid (clopyralid); 2-chloro- N -(2-ethyl-6-methylphenyl)- N -(2-methoxy-1-methylethyl)acetamide (metolachlor); 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl) benzene (oxyfluorfen); N- (1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine (pendimethalin); O -(6-chloro-3-phenyl-4-pyridazin-yl) S -octylcarbonothioate (pyridate); 2,6-dinitro- N , N -dipropyl-4-(trifluoromethyl)benzenamine (trifluralin).