SELETIVIDADE E EFICIÊNCIA DO HERBICIDA FLUMICLORAC-PENTIL NO CONTROLE DE Euphorbia heterophylla L. NA CULTURA DE SOJA

Abstract

The selectivity and efficacy of flumiclorac-pentil applied alone and as tank mixture with imazethapyr or cloransulam-metil on Euphorbia heterophylla L. were studied under field conditions. The study was conducted during the 2000/2001 growing season. The experimental design was a randomized completely block with four replications. The treatments (rate of active ingrediente per hectare) consisted of flumiclorac-pentil (60 gi.a./ha), flumiclorac-pentil (40 g) + imazethapyr (59,5 g), flumiclorac-pentil (40 g) + cloransulam-metil (30 g), imazethapyr (98 g) and cloransulam-metil (41 g). A check and a hoed treatment were included. The treatmens that included flumiclorac-pentil (applied alone and as tank mixture with the herbicides) plus Assist at 0,5 % (mineral oil) caused higher injury to the crop which varied from 27,0 to 33,7 % at the assessment carried-out at 5 days after treatment applicatio (DAT). The injury symptoms were identified as curling and scorch mainly in recently emerged leaves. At 14 DAT, the crop was recovering from the symptoms which were seen just in older leaves. All treatments showed more than 95 % and 92,0 % E. heterophylla control at 15 and 30 DAT However, at 30 DAT, flumicloracpentil, applied alone, gave poorer control and was statistically inferior Sto the other herbicide treatments but still with 92,5 % weed control. The same treatment behaviour was observed at 60 DAT. The soybean plants recovered from the initial phytotoxicity caused by flumiclorac-pentil treatments and there was no effect on the grain yield.