Responses of cole crops to pre-transplant herbicides

There are few pre-transplant herbicides for weed control in cole crops in Ontario. Three field trials were established each year in 2003, 2004, and 2005 at Ridgetown, Ontario, Canada to evaluate broccoli, cabbage, and cauliflower tolerance to oxyfluorfen (560 and 1120 g a.i./ha), dimethenamid-p (750 and 1500 g a.i./ha), sulfentrazone (100 and 200 g a.i./ha), and a tank-mix of dimethenamid-p plus sulfentrazone (750+100 and 1500+200 g a.i./ha), representing once and twice the proposed use dose for each herbicide/tankmix. Treatments included a non-treated weed-free control. Oxyfluorfen, dimethenamid-p, sulfentrazone, and dimethenamid-p plus sulfentrazone applied pre-transplant at the proposed and twice the proposed use dose in broccoli, cabbage, and cauliflower did not cause any visual injury, and did not reduce number of heads produced, head weight or yield in all nine trials conducted. Based on these results, oxyfluorfen, dimethenamid-p, sulfentrazone, and dimethenamid-p plus sulfentrazone all have an acceptable level of crop safety for use at the proposed dose in broccoli, cabbage, and cauliflower.