Abstract

MACIEL, C.D.G. et al. Efficiency and selectivity of trifloxysulfuron sodium + ametryne and hexazinone + diuron herbicide as a result of application technology and mechanical management of sugarcane straw in the crop row. Planta daninha [online]. 2008, vol.26, n.3, pp. 665-676. ISSN 0100-8358.  http://dx.doi.org/10.1590/S0100-83582008000300023.

Aiming to optimize the use of trifloxysulfuron sodium + ametryne and hexazinone + diuron following adoption of different spray nozzles and sugarcane straw management in the crop row, two experiments were conducted at Parálcool Sugar Mill S/A in Paraguaçu Paulista/SP. In Experiment 1, twelve treatments arranged in a 2 x 2 x 3 factorial scheme were performed, with four replications to evaluate the presence and absence of sugarcane straw in the crop row, and use of the herbicides trifloxysulfuron sodium + ametryne (37 + 1463 g ha-1 and 0.2% v/v of Aterbaneâ) and diuron + hexazinone (330 + 1170 g ha-1 and 0.2% v/v of Aterbaneâ) and spray nozzles XR11002-VS (128 L ha-1), AI11002-VS (200 L ha-1) and TF-VP5 (310 L ha 1). In Experiment 2, The application of spraying solution on sugarcane and Digitaria horizontalis plants, generated by the combination of the herbicides and the spray nozzles, was monitored by using a tracer solution constituted by coloring FDC-1 + herbicide. The results suggest that the crop straw provided excellent control of the infesting species, even in the absence of herbicide treatment. For D. horizontalis (6 leaves to 1-2 tillers) and Brachiaria decumbens (2 to 6 leaves) chemical control was efficient (>91%) in the rows without straw, after 14 DAA (days after application) for the herbicides and spray nozzles studied. D. horizontalis was more quickly controlled at 7 DAA by using trifloxysulfuron sodium + ametryne with AI11002-VS spray nozzle. Crop injury was observed up to 21 DAA, becoming more intense when diuron + hexazinone combinedwith AI11002-VS and TF-VP5 nozzle were used, due to higher herbicide deposition on the crop leaves.

Keywords : sugarcane; mulch management; herbicide; spray nozzles.