The present research was conducted in two assays, with the herbicides trifluralin, nitralin and EPTC in two dosi, to verify the weed control, to observe the possible phytotoxicity effects on the crop after re-application in the same agricultural year, and to determine the possible residues in the soil, in the beginning of the next agricultural year, that might affect suceptible subsequent crops. The determination of possible residues in the soil was made by root and shoot bioassays using the sorghum (Sorghum bicolor (L . ) Moench. ) as test plant. There was a good control of weeds by the herbic ides. The purple nutsedge (Cyperus rotundus L.) was controlled only by EPTC. Spanish needles (Bidenspilosa L. ) and broom weed (Sida spp) were not controlled by the herbicides. None of herbicides presented phytotoxic it y effects to the bean crops even after re-applications in the same agricultural year, and residues were not found in the next agricultural year, after re-application in the prior year.
Herbicides; Bean; Persistence