Evaluation of herbicide efficacy and selectivity in sunflower (Helianthus annuus L.) crops.
On a silty sand loam with 1.8% OM, infested mainly with Brachiaria plantaginea and Cenchrus echinatus, 0.9 kg trifluralin incorporated pre-sowing, 1.8 kg trifluralin, 3.36 kg alachlor and 2.16 kg metolachlor/ha all pre-em. selectively controlled the weeds in sunflowers. C. echinatus was more sensitive to 2.16 kg flurochloridone/ha than B. plantaginea. Although no adverse effects on sunflower height and only slight decrease in flower diam. were observed, yields from treated plots were little higher than from the unweeded control.