EFFECT OF WEED COMPETITION AND WEED CONTROL PROGRAMS ON RUTABAGA YIELD

Abstract

The effects of different periods of weed competition and of trifluralin (α,α,α-trifluro-2,6-dinitro-N,N-dipropyl-p-toluidine), niclofen (2,4-dichloro-phenyl-p-nitrophenyl ether), and cultivations were studied for effects on yield of rutabaga (Brassica napobrassica Mill. ’York’). Delaying weed removal for 4 wk after crop emergence significantly reduced yields of marketable and total roots compared with plots kept weed-free all season. Delayed weeding beyond 4 wk resulted in progressively greater reductions in yield. Rutabagas kept weed-free for 2, 4, 6, and 8 wk from crop emergence by once-weekly weeding gave yields comparable to those kept weed-free all season. Herbicide treatments without hand-weeding gave significantly lower yields than those with one hand-weeding. The use of three hand-weedings with herbicides was not significantly better than herbicides with one hand-weeding. Level of weed control was dependent on weed species present in the test area; however, a combination of trifluralin and niclofen gave a broader spectrum of control and better crop yields than either used alone.