Weed Control in Carrot (Daucas carota L.): Bio-efficacy and Residues of Pre-emergence Herbicides

摘要

A field experiment was conducted at Ludhiana during winter 2007-08 to evaluate the bio-efficacy of four pre-emergence herbicides in carrot. Pendlmethaiin 0.375,0.562 and 0.750 kg ha~(-1) trifluralin 0.600,0.900 and 1.200 kg ha~(-1), alachlor 1.250,1.875 and 2,500 kg ha~(-1) oxyfluorfen 0,117, 0.147 and 0.176 kg ha~(-1) two hand hoeing (20 and 40 days after sowing) and unweeded control were evaluated in RBD. All the herbicidal treatments reduced the weed dry matter accumulation significantly as compared to unweeded control. The season long weed competition reduced the carrot root yield from 11,5 to 26.1 per cent. All the herbicidal treatments except pendlmethaiin 0.375 kg and trifluralin 0.600 kg ha~(-1) recorded total carrot root yield at par with hand hoeing but significantly higher than the unweeded control. Oxyfluorfen 0.147 kg ha~(-1) recorded the highest root yield (269, q ha~(-1)) which was at par with oxyfluorfen 0,117 & 0.176 kg ha~(-1), pendlmethaiin 0.562 and 0.750 kg ha~(-1), trifluralin1.200 kg ha' and alachlor at all levels. As compared to unweeded control, the increase In carrot root yield under herbicidal treatments varied from 13,1 to 35.5 per cent. The herbicides did not influence total soluble solids and carotene contents in carrot roots. Residues of pendlmethaiin, trifluralin and oxyfluorfen in carrot roots were below detectable level, Alachlor residues were not analyzed in the present study.