EXPLORAÇÃO DO RESIDUAL DE FLUMIOXAZINA POR MEIO DE DOSES E ASSOCIAÇÕES A OUTROS HERBICIDAS EM PRÉ-EMERGÊNCIA NA SOJA

Abstract

The herbicide flumioxazin has been an important tool to the control of resistant- and tolerant weeds in preemergent treatments for soybean crop. However, a few information about the efficiency and selectivity of this herbicide with high rates and in combination to other residual herbicides is available. The objective of this study was to evaluate the efficacy and selectivity of flumioxazin in high rates in mixture with other products, in two soybean cultivars. Fourteen treatments composed by two flumioxazin rates (150 and 200 g ha-1) and twelve more mixtures treatments were applied on “applied-planted” system. Two similar experiments were conducted, one with the cultivar M7739IPRO and a second one with the cultivar Brasmax Desafio 8473RR. Absolute density and absolute frequency of weeds were calculated for each treatment 20 days after crop emergency. Crop injury, crop height and yield were estimated to verify the treatments selectivity. The predominant weed at experimental sites was Cenchrus echinatus, which demonstrated difficult control for all treatments applied. Except for this species, the remained weeds present in both experiments were efficiently controlled by all treatments. For the cultivar Monsoy M7739 IPRO, the selective treatments were flumioxazin only (150 or 200 g ha-1), flumioxazin + S-metolachlor (150 + 1152 or 200 + 2304 g ha-1), and flumioxazin + imazetapyr (150 + 106 g ha-1). For the cultivar Brasmax Desafio 8473RR, all herbicides treatments were considerate selective. It is needed to considered what cultivar is being sown as well as the weed community in each area for the choice of flumioxazin application alone or in mixture with other residual herbicides.