Sistemas de manejo de plantas daninhas utilizando o novo herbicida pyroxasulfone visando ao controle químico de gramíneas em soja

Due to the increasing number of grasses selected for resistance to the EPSPS and ACCase inhibitors, new alternatives with effective and selective herbicides from different mechanisms of action must be developed. This work was carried out to evaluate weed management systems containing the new herbicide pyroxasulfone aiming at controlling goosegrass ( Eleusine indica ) and sourgrass ( Digitaria insularis ) in applications immediately prior to soybean sowing. The design used for the randomized blocks, with eleven treatments and four replicates. All residual herbicides were applied at the second burndown application, seven days prior to soybean sowing. In each system, two sequential burndown applications followed by one post-emergence application were sprayed in each treatment. The best level of initial (up 28 days after crop sowing) control of goosegrass was observed with treatments with pyroxasulfone, although after the third herbicide application all systems provided excellent control of this weed. Concerning to sourgrass, the third post-emergence application did not provide any weed control improvement and the best results were found where residual herbicides were applied at the second burndown application, except with chlorimuron-ethyl. Associations with pyroxasulfone with other residual herbicides is an excellent option to provide simultaneous control of goosegrass and sourgrass, and those treatments are selective for soybeans.