A study was conducted from September to December 1997, in Pentecoste, Ceara, Brazil, to determine the effectiveness of the herbicides glyphosate (1800 g ha -1) and paraquat (800 g ha -1), applied as desiccants before sowing, and fenoxaprop-P-ethyl [fenoxaprop-P] (0, 40, 80 and 120 g ha -1) and imazamox (0, 21, 42 and 63 g ha -1), applied in post-emergence conditions, in controlling the weeds and to evaluate the phytotoxicity of the herbicides to cowpea plants ( Vigna unguiculata cv. Epace 10) under a no-tillage system with furrow irrigation. The treatments with glyphosate associated with imazamox or fenoxaprop-P-ethyl was more efficient in controlling the weeds, showing reduced weed shoot dry biomass production, when compared to paraquat combined with the post-emergence herbicides. Fenoxaprop-P-ethyl and imazamox did not cause visual phytotoxicity symptoms to the cowpea plants. The best post-emergence weed control was provided by fenoxaprop-P-ethyl at the rate of 80 g ha -1, associated with glyphosate (1800 g ha 1). Fenoxaprop-P-ethyl was effective against the grass weeds, but not against Cenchrus echinatus and Digitaria horizontalis. Imazamox was not effective in controlling the broadleaf weeds Chamaesyce hirta and Euphorbia heterophylla at the studied rates.
