HERBICIDES APPLIED ALONE AND IN ASSOCIATION FOR THE LATE POST-EMERGENCE CONTROL OF Merremia aegyptia AND Urochloa decumbens

Resumen

Weed interference is one of the main factors limiting sugarcane (Saccharum officinarum L.) performance, making chemical control an important practice for weed management. This study aimed to evaluate the efficacy of herbicides applied alone and in association for the late post-emergence control of Merremia aegyptia and Urochloa decumbens. The experiment was conducted under greenhouse conditions in pots using a completely randomized design in a two by six factorial arrangement, with four replications. The first factor consisted of the weed species Merremia aegyptia and Urochloa decumbens, and the second factor consisted of the herbicide treatments: untreated control, tebuthiuron, sulfentrazone, clomazone, tebuthiuron + atrazine, and tebuthiuron + sulfentrazone. The evaluated variables were visual control at 7, 14, 21, and 28 days after application (DAA) and shoot dry mass at 28 DAA. Significant effects of herbicides and of the interaction between weed species and herbicides were observed at all evaluation times. Urochloa decumbens showed greater initial control, whereas no significant differences between species were observed at 21 and 28 DAA. At the end of the experimental period, tebuthiuron, sulfentrazone, clomazone, and tebuthiuron + atrazine provided the highest control levels, whereas tebuthiuron + sulfentrazone showed lower performance. All herbicide treatments reduced shoot dry mass compared with the untreated control. Under the conditions of this experiment, tebuthiuron + atrazine, sulfentrazone, tebuthiuron, and clomazone were effective for the late post-emergence control of Merremia aegyptia and Urochloa decumbens.