This work aimed to study the agronomic efficacy of herbicides applied in raw sugarcane harvest areas, to control Ipomea quamoclit and Bidens pilosa, on a commercial sugarcane farm with clayey textured soil in Araras-SP. The herbicides (in g ha-1) were trifloxysulfuron-sodium + ametryn (27,77 + 1,097 and 37 + 1,463), mesotrione (120 and 192), mesotrione + ametryn (120 + 1,500), mesotrione + trifloxysulfuron-sodium + ametryn [120 + ( 27,77 + 1,097)], trifloxysulfuron-sodium + ametryn +diuron + hexazinone [(27,77 + 1,097) + (702 + 198)] and metribuzin (1,920) were applied in weed preemergence on the sugarcane straw; in weed preemergence on the soils ans afterwards covered with straw; and in weed postemergence, using a direct sprayer between the crop lines (approximately 30 cm high). Based on the results obtained, it was concluded that herbicide application on sugarcane straw and in weed preemergence altered the efficacy of mesotrione at 120 g ha-1, of trifloxysulfuron sodium + ametryn (27,77 + 1,097 g ha-1) and of the mixtures mesotrine + ametryn and mesotrione + (trifloxysulfuron sodium + ametryn); the herbicides metribuzin and (trifloxysulfuron sodium + ametryn) + (diuron + hexazinone) were effective in controlling the weeds, regardless of the mode of application. The weed species B. pilosa was the most susceptible to the herbicides and to the raw sugarcane harvest system, i.e., straw on the soil inhibited its establishment. The herbicides applied using a direct sprayer between crop lines in postemergence were selective for the crop.
I. quamoclit; Bidens pilosa; leaching; straw
