California Agriculture

DCPA was the principal preemergence herbicide for controlling weeds in onions until its manufacture was discontinued in 1996, although it may be reintroduced in 2001. The purpose of this research was to test the effectiveness of a combination of two herbicides, bensulide and pendimethalin, as a replacement weed-control treatment. Results are encouraging; this combination performed as well as DCPA in 12 onion field trials conducted in the Imperial Valley. Onion yields in fields treated with bensulide and pendimethalin were comparable to that of fields treated with DCPA.