Performance de associa??es de herbicidas em cana-de-a?úcar (Saccharum officinarum)

摘要

The present work was aimed to evaluate the selectivity and efficiency of herbicides mixtures in sugar cane variety RB 83-5486. Four experiments were carried out in Nova Londrina (PR) and Marilena (PR). In each locality were developed two experiments. The experiments were conducted in randomized blocks, with nine treatments and four replications. In all experiments, the treatments were applied in pre-emergence: T1 (tebuthiuron) + (hexazinone + diuron), T2 (clomazone + ametrina) + (clomazone), T3 (clomazone + ametrina), T4 (trifloxysulfuron sodium + ametrina), T5 (trifloxysulfuron sodium + ametrina) + (hexazinone + diuron), T6 (clomazone + ametrina) + (hexazinone + diuron), T7 (hexazinone + diuron) + (clomazone), and two untreated?checks (T8 - weedy and T9 – weed-free). Most treatments caused phytotoxicity in the culture. However, in all experiments, the crop recovered from the phytotoxicity caused by chemical treatments at 100 days after the application. T1 and T7 (Nova Londrina) and T5 and T6 (Marilena) provided total control of weeds up to 100 DAA. In both localities, the biomass accumulation at 150 DAA of the herbicides indicated no significant differences, in comparison with the weed-free ckeck. The weed interference reduced sugar cane biomass from 49,9% (Nova Londrina) to 56,2% (Marilena).