Field experiment was carried out at Agricultural College Research Institute, TNAU, Killikulam during kharif 1993 and 1994 to evaluate the bio-efficacy of pre-emergence herbicides viz., thiobencarb, butachlor, pretilachlor and pendimethalin. These herbicides effectively controlled all categories of weeds over control (puddling alone). Among various herbicides, pretilachlor plus safener 0.5 kg/ha applied on 8 days after sowing (DAS) was most effective due to its effective weed control, high selectiveness to rice and greater dry matter accumulation in rice seedling. This was followed by pretilachlor plus safener 0.5 kg/ha applied on 4 DAS and thiobencarb 1.0 kg/ha applied on 8 DAS.
