CONTROL OF WEEDS IN SUGAR CANE WITH HERBICIDES APPLIED IN PRE-EMERGENCE

Abstract

In sugar cane crop, the weeds may interfere with the stem and sugar productivities, and the use of herbicides is one of the most indicated management methods to fight them. However, some herbicides can cause phytotoxicity to the crop, damaging the production of economic interest. In order to evaluate the effectiveness and the selectivity of herbicides applied to pre-emergence of sugarcane as well as the productivity of sugar cane crop, an experiment was conducted in Usina Santa Helena de Açúcar e Álcool S/A, located in Santa Helena de Goias - GO. The results indicated that all the herbicides were selective with sugarcane ratoon when applied in cultivation pre-emergency and, considering the set of weeds Alternanthera tenella, Acanthospermum hispidum and Commelina benghalensis, the largest percentages of control  were obtained in treatments with herbicides hexazinone + clomazone (300 + 1.200 g i.a. ha-1), sulfentrazone + clomazone (500 + 1.000 g i.a. ha-1) e sulfentrazone puro (900 g i.a. ha-1). Except for clomazone (1.250 g i.a. ha-1) e clomazone + ametrina (1.200 + 1.800 g i.a. ha-1), all the herbicides and dosages tested were equally efficient in controlling the weed community. The stem and sugar productivities were probably not influenced by treatments with herbicides or weeded plots when compared with the weeded check. Keywords: Saccharum spp., Chemicals, selectivity