A field trial was performed, on a oxisol (Latos - solic B) containing 4.82% organic matter, with the objetive to verify the weed control with pre and postemergence herbicides in upland rice cv "Pratão Precoce". The following treatments were used (kg a.i/ha) : pendimethal in at 0,75, 1,00 and 1,50; AC-92390 at 1,00, 2,00 and 3,00; butachlor at 2,05; benthiocarb at 4,50; oxadiazon at 1,0; in pre-emergence and propanil at 4,32; propanil + 2,4 -D amine at 2,88 + 0,36, and propanil + parathion methyl at 1,98 + 0,24. in postemergence 29 days after planting. The predominant weeds were: Acanthospermum hispidum D.C. , Commelia sp, Cassia patellaria D.C, Indigofera hirsuta L., Cenchrus echinatus L., Portulacca oleracea L. and Sida sp. Only the postemergence treatments controlled Acanthospermum hispidum D.C, but Cassia patellaria D.0 was controlled by butachlor and the postemergence treatments . The best total weed control were obtai ned by the postemergence treatments. The preemergence treatments were hoed at 36 days after planting and the postemergence treatments at 54 days. The treatment with propanil + parathion methyl presented fitotoxicity 5,8 by the EWRC scale, but there wasn't significative difference between the treatments with herbicides in grain yield.
herbicides; upland rice; interaction herbicide x inseticide