This work aimed to develop a strategy for weed management in conventionally tilled cotton by combining the herbicides S-metolachlor in pre-emergence and trifloxysulfuron-sodium in post-emergence. Fourteen treatments were evaluated arranged in a factorial scheme 3 (three doses of S-metolachlor 384; 768 and 1,152 g ha-1 x 4 (four doses of trifloxysulfuron-sodium 0.0; 2.625; 5.250 and 7.875 g ha-1, plus two controls (with and without weeds throughout the cotton planting cycle). The following weed species were present in the area: Alternanthera tenella, representing over 80% of the total, Bidens sp., Acanthospermum hispidum, Cenchrus echinatus, Digitaria horizontalis, Eleusine indica e Commelina benghalensis Smetolachlor controlled A. tenella, C. echinatus, D. horizontalis, E. indica and C. benghalensis with high efficiency. Trifloxysulfuron-sodium controlled the dicotyledonous species effectively. The treatments providing the highest productivity were S-metolachlor at 768 g ha-1 plus 7.875 g ha-1 trifloxysulfuron-sodium; S-metolachlor at 1,152 g ha-1 plus trifloxysulfuron-sodium at the doses 5.250 and 7.875 g ha-1. The best weed control was obtained with 1,152 g ha-1 S-metolachlor plus 7.875 g ha-1 trifloxysulfuron-sodium.
competition; Gossypium hirsutum; selectivity
