Herbicidas alternativos para o controle de Conyza sumatrensis (Retz.) E. H. Walker resistentes aos inibidores da ALS e EPSPs

Abstract

Herbicidas alternativos para o controle de Alternative herbicides to control Conyza sumatrensis (Retz.) E. H. Walker resistant to and EPSPs inhibitorsHorseweed (Conyza sumatrensis), one of the major weeds identified in southern Brazil, has not been adequately controlled with the herbicides chlorimuron-ethyl and glyphosate. In this context, the aim of this study was to evaluate alternative herbicides for the control of C. sumatrensis biotypes with low resistance to the herbicide chlorimuronethyl and resistant to glyphosate. The experiment was carried out in a greenhouse, between April and August 2012, in Passo Fundo / RS. The experimental design was the completely randomized with four replications, with 15 herbicide treatments, and an untreated control. The variables evaluated were percent control at 14, 21 and 28 days after treatment (DAT) and dry weight of shoot at 28 DAT. The results showed that the biotypes were 100% controlled at 28 DAT by the alternative treatments of paraquat + diuron, ammonium glufosinate, glyphosate + 2,4-D, glyphosate and ammonium glufosinate; 2,4-D; tembotrione and tembotrione + atrazine. The biotype 17 showed less sensitivity to ALS-inhibiting herbicides, and biotypes 05, 17 and 20 were not controlled by glyphosate.

Management Programs to Control Conyza spp. in Pre-Soybean Sowing Applications

“…plants; in turn, for experiments E3 and E4, these treatments were efficient (> 90%) and did not differ from the others. In the western part of Paraná (region of experiments 1 and 2), there were cases of control deficiency when associating chlorimuronethyl and glyphosate, and this may be related to the presence of glyphosate and chlorimuronethyl resistant biotypes of Conyza sumatrensis (Santos et al, 2015). Equal lowercase letters in the column do not differ by Tukey's test (p≤0.05).…”

“…biotypes collected in different municipalities in the State of Paraná, observed that they were controlled differently by the herbicide glyphosate; some biotypes had higher sensitivity and others lower sensitivity to the herbicide. In the same context, Santos et al (2015) evaluated the control of Conyza sumatrensis when subjected to the action of chlorimuron-ethyl and glyphosate, and control results also showed variability.…”

Management of Glyphosate-Resistant Hairy Fleabane and Contribution of the Physiological Potential of Seeds to Resistance

“…Vargas et al (2007) also obtained favorable results with the application of 2,4-D, paraquat, chlorimuron-ethyl, and metsulfuronmethyl at early developmental stages of Conyza sp. Meanwhile, a significant loss of C. sumatrensis control with chlorimuron-ethyl has been reported in plants taller than 10 cm due to the higher density of foliar trichomes, which blocked herbicide penetration (SANTOS et al, 2015). Paraquat and diquat were more effective when applied to smaller plants, reaching control close to 100% at stages I and II of development in both biotypes (Table 1).…”

Mistura Em Tanque E Interações Entre Herbicidas

“…O herbicida mais utilizado na dessecação é o glifosato, um herbicida sistêmico e não seletivo e de amplo espectro (DUKE e POWLES, 2008). (MOREIRA et al, 2007;TAKANO et al, 2013;BRESSANIN et al, 2014 ;SANTOS et al, 2015).…”