Sumatran Fleabane Control using Glyphosate in Association with Halauxifen-Methyl Formulations

Abstract

The effectiveness of a new product has a great importance to weed control, especially those that are difficult to control or resistant to, such as the sumatran fleabane (Conyza sumatrensis). The objective of this research was to evaluate the control of C. sumatrensis at different growth stages, using halauxifen-methyl in combination with other herbicides. The experimental design used was a randomized blocks in a 3x10 factorial scheme, with four replications. The plants of C. sumatrensis were evaluated at different growth: stage 1: plants with 8 leaves; Stage 2: plants with 19 leaves and stage 3: plants with 45 leaves fully expanded. The herbicides used were the association of glyphosate with the herbicides 2,4-D at 806, 943 and 1,209 g a.e. ha-1, halauxifen-methyl + diclosulam at 5.06 g a.e. ha-1 + 25.52 g a.i. ha-1 and 6.32 g a.e. ha-1 + 31.87 g a.i. ha-1, halauxifen-methyl + 2,4-D at 5.00 + 783 g a.e. ha-1 and 6,0 + 940 g a.e. ha-1 and halauxifen-methyl at 5.0 and 6.0 g a.e. ha-1 and untreated, totaling 10 treatments. The herbicides demonstrated satisfactory control of the plants in Stage 1 at 50 DAA, with the exception of the glyphosate + 2,4-D treatment at the lowest rate. However for Stages 2 and 3 the halauxifen-methyl + diclosulam in both rates, provided superior controls in relation to the other treatments. The control of sumatran fleabane was facilitated when their management occurs in the early stages of development, however independent of the development stage, the best controls obtained were with the treatment containing glyphosate + halauxifen-methyl + diclosulam at 1,440 g a.e. ha-1 + 6.32 g a.e. ha-1 + 31.87 g a.i. ha-1. Thus, combinations of herbicides containing halauxifen-methyl are another option to control C. sumatrensis in agricultural systems.

Can Control of Glyphosate Susceptible and Resistant Conyza sumatrensis Populations Be Dependent on the Herbicide Formulation or Adjuvants?

“…sumatrensis infestations concern farmers, advisors, plant protection companies and policy makers, because worldwide this species has evolved resistance to herbicides of many different modes of action, such as photosystem II (PSI) electron diverters, acetolactate synthase (ALS) inhibitors, protoporphyrinogen oxidase (PPO) inhibitors, synthetic auxins and EPSPS inhibitors, leading to common treatment failures [14]. The recent herbicide resistance cases in Sumatran fleabane are ever-increasing, with the species demonstrating high levels of resistance to active ingredients such as paraquat [31] and glyphosate [5]. Thus, extensive research should be conducted regarding alternatives and additives to glyphosate in order to moderate glyphosate resistance evolution in C. sumatrensis as in other noxious weeds.…”

“…The proper use of adjuvants is imperative in cases of glyphosate applications, since they reduce the surface tension of the spray liquid and may improve the efficacy of the treatments [32]. Sumatran fleabane has been reported to be more sensitive to glyphosate in earlier rather than more advanced growth stages, due to altered morphological characteristics of the leaf tissues and subsequently lower deposition of the herbicide [13,31,32]. The dose-response assays in the present study revealed that the susceptibility of C. sumatrensis to herbicidal treatments at the rosette stage (BBCH [16][17][18] varied among populations and depended on the glyphosate formulation and the addition of adjuvants.…”

Halauxifen-Methyl+Diclosulam: New Option to Control Conyza spp. Prior Soybean Sowing

“…However, although the results in Tables 4, 5 and 6 showed that treatments with pre-mix halauxifen-methyl + diclosulam at V 1 growth stage provided better control than the other standard treatments, similar results were found when using the pre-mix halauxifen-methyl + diclosulam in different doses, for Conyza spp. control (Braz et al, 2017;Zobiole et al, 2018a;Zobiole et al, 2018b). It was noticed that the treatments without 2,4-D were not as effective as those associated with 2,4-D, and such results agree with the studies of Chahal and Johnson (2012) and Eubank et al (2008), in which there was a better performance of herbicides when 2,4-D was used in the burndown application.…”

“…Such results corroborate others, in which there was a reduction of Conyza spp. dry weight caused by the application of other auxinic herbicides such as halauxifen-methyl + diclosulam, dicamba, 2,4-D amine and 2,4-D ester and (Chahal and Johnson, 2012;Braz et al, 2017;Zobiole et al, 2018a).…”

Strategies of chemical management for weed control in cassava

“…Ceres, Viçosa, v. 67, n.3, p. 240-246, may/jun, 2020 However, due to the reduced number of herbicides registered, the adoption of chemical management strategies of weed, as an example the sequential application of isolated or mixed herbicides, may contribute to enlarge control spectrum, improving the residual effect, besides the different action mechanisms, in a way to avoid the selection of resistant weed biotypes (Beckie & Harker, 2017). As well as Zobiole et al (2018), which evaluated the association between halauxifen-methyl with other herbicides in the control of Coniza sumatrenis and obtained satisfactory results, with highlight to glyphosate+halauxifen-methyl+diclosulam (1,440+6.32+31.87 g a.i. ha -1 ), which allows the implementation of a new tool in the management of this weed which is hard to control.…”