Eficácia do S-metolachlor associado à ametrina e hexazinona+diuron no controle pré e pós-emergente de plantas daninhas em cana-de-açúcar

Abstract

The work aimed to evaluate, in sugar cane crop, the selectivity and effectiveness of S-metolachlor herbicide associated to ametryn and [hexazinone+diuron], applied terrestrial and aerial forms, in pre and post emergent weeds control. The experimental design used in experiment 1 (terrestrial application) was randomized complete blocks with 16 treatments and four repetitions, applied in pre and post emergence: S-metolachlor + ametryn (1920 + 1500; 2400 + 1500 and 2880 + 1500 g a.i. ha -1 ; S-metolachlor + [ hexazinone+diuron ] (1440 + [ 702+198 ] and 1920 + [ 702+198 ] g a.i. ha -1 ; [ hexazinone+diuron ] + ametryn ([ 936+264 ] + 1500 g a.i. ha -1 ; tebuthiuron + ametryn (1000 + 1500 g a.i. ha -1 and checks with and without weeding. In experiment 2 (aerial application), the treatments were constituted by S-metolachlor (2880 g a.i. ha -1 ), S-metolachlor + ametryn (2400 + 1500 g a.i. ha -1 ) and checks without application, being herbicides applied in two bands of one hectare for each treatment. All herbicides treatments caused initial phytotoxicity to sugar cane crop (RB 835486), with total recovery at 45 DAA (days after application). Terrestrial application in S-metolachlor + ametryn, S-metolachlor + [hexazinone+diuron], [hexazinone+diuron] + ametryn and tebuthiuron + ametryn pre-emergence was efficient in controlling Digitaria horizontalis , Ipomoea nil and Amaranthus deflexus. In post emergency, treatments were less efficient in controlling D. horizontalis; more efficient in controlling I. nil and equivalents in A . deflexus control. Aerial application of S-metolachlor and S-metolachlor + ametryn was efficient in D. horizontalis e B. plantaginea control, providing higher sugar cane yield than the check without herbicides application.