Herbicide selectivity: II - herbicide application at initial and late and post-emergence of sugarcane in the rainy season

摘要

This research aimed to evaluate the selectivity of azafenidin+hexazinone, diuron+hexazinone, metribuzin and isoxaflutole to sugarcane, applied at initial and late post-emergence during the rainy season. The study was conducted over 3-yr sugarcane ratoons (cv. RB 835089), in Araras, SP. The experiment was arranged in randomized blocks with five treatments and four replications, and one weeded control for each treatment within each block. The treatments used were: (diuron+hexazinone (1,170 + 330 g ha-1), azafenidin+hexazinone (192.5+247.5 g ha-1), metribuzin (1,920 g ha-1) and isoxaflutole (127.5 g ha-1) and weed control. It was concluded that the herbicides damaged sugarcane the most when applied during late post-emergence. At early post-emergence, isoxaflutole was the only herbicide affecting yield. In late post-emergence, all the herbicides affected yield, with diuron+hexazinone being the only one that did not affect sugarcane technological characteristics and yield