Response of Nebraska Horseweed (Conyza canadensis) Populations to Dicamba

Crespo, Roberto; Bernards, Mark L.; Kruger, Greg R.; Lee, Donald; Wilson, R. G.

doi:10.5539/jas.v5n5p158

Cited by 4 publications

(2 citation statements)

References 13 publications

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“…In no-tillage fallow, control of annual weeds increases by applying residual herbicides combined with glyphosate [5] [24] [25]. Many of the residual herbicides for Conyza spp.…”

Section: Introductionmentioning

confidence: 99%

Differential Susceptibility of <i>Conyza bonariensis</i> Biotypes to Glyphosate and ALS-Inhibiting Herbicides in Argentina

Puricelli¹,

Faccini²,

Metzler³

et al. 2015

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The aim of this study was to compare control of three stages biotypes (rosette, bolting, and reproductive stage) of Conyza bonariensis glyphosate susceptible biotype (S) and tolerant biotype (T) to glyphosate with glyphosate and mixtures of acetolactate synthase (ALS)-inhibiting. For glyphosate, the dose-response curves confirmed that injury of the biotype T relative to biotype S was significantly lower for both rosette and bolting stages. Resistance index (RI) for this herbicide was approximately 4 for both weed stages. At bolting, for both biotypes doses much higher than the recommended dose were required. For acetolactate synthase (ALS)-inhibiting herbicides, at the rosette stage, control of both biotypes was excellent with doses significantly lower than the recommended rate. All herbicides within this group showed a very low I50 relative to the recommended rate. These results indicate that biotypes difficult to control with glyphosate at the rosette and bolting stage may be controlled using acetolacte synthase (ALS)-inhibiting herbicides. Control for the reproductive stage was poor. A management program based on the combination of glyphosate with pre-and post-emergence acetolactate synthase (ALS) herbicides may be effective to control the weed.

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“…In no-tillage fallow, control of annual weeds increases by applying residual herbicides combined with glyphosate [5] [24] [25]. Many of the residual herbicides for Conyza spp.…”

Section: Introductionmentioning

confidence: 99%

Differential Susceptibility of <i>Conyza bonariensis</i> Biotypes to Glyphosate and ALS-Inhibiting Herbicides in Argentina

Puricelli¹,

Faccini²,

Metzler³

et al. 2015

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“…Over the 2 yr of study, the most consistent herbicide treatments were the 600 g ha −1 rate of dicamba and saflufenacil applied at rates of 74.8 and 101.1 g ha −1 when paired with tillage treatments or cereal rye cover crops. Crespo et al (2013) developed a doseresponse equation evaluating dicamba's effect on 10 Nebraskan C. canadensis populations. They calculated that, on average, to achieve 90% visual control, a rate of dicamba of 560 g ha −1 or more was required.…”

Section: Response Of Individual Selection Pressuresmentioning

confidence: 99%

An integrated weed management strategy for the control of horseweed (Conyza canadensis)

et al. 2020

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Multiple herbicide-resistant populations of horseweed [Conyza canadensis (L.) Cronquist] continue to spread rapidly throughout Ontario, notably in areas where no-till soybean [Glycine max (L.) Merr.] is grown. The occurrence of multiple herbicide resistance within these populations suggests that the future role of herbicide tank mixtures as a means of control will be limited. An integrated weed management strategy utilizing complementary selection pressures is needed to reduce the selection intensity of relying solely on herbicides for control. Field studies were conducted in 2018 and 2019 to test the hypothesis: if fall-seeded cereal rye (Secale cereale L.) can reduce C. canadensis seedling density and suppress seedling growth, then the interaction(s) of complementary selection pressures of tillage, cereal rye, and herbicides would improve the level of C. canadensis control. Laboratory studies were conducted to determine whether the allelopathic compound 2-benzoxazolinone (BOA) affected the root development of C. canadensis seedlings. The interactions observed among multiple selection pressures of tillage, cereal rye, and herbicides were inconsistent between the 2 yr of study. A monoculture of cereal rye seeded in the fall, however, did reduce seedling height and biomass of C. canadensis consistently, but not density. This reduction in seedling height and biomass was likely caused by the allelopathic compound BOA, which reduced seedling root development. Control of C. canadensis seedlings in the spring required the higher registered rates of dicamba or saflufenacil. The addition of shallow fall tillage and the presence of cereal rye did not improve the variability in control observed notably with 2,4-D or the lower rates of saflufenacil or dicamba. With the implementation of complementary weed management strategies, environmental variables in any given year will likely have a direct influence on whether these interactions are additive or synergistic.

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Droplet Spectrum Generated by Air Induction Nozzles Spraying Solutions Containing Adjuvants and a Tank Mixture of Glyphosate and Dicamba

Antuniassi

Mota²,

Chechetto³

et al. 2020

Pesticide Formulation and Delivery Systems: 40th Volume, Formulation, Application and Adjuvant Innovation

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The aim of this work was to evaluate drift reduction technologies (DRTs) by analyzing the droplet spectrum generated by air induction nozzles spraying solutions containing adjuvants and a mixture of glyphosate and dicamba. The TTI and AIXR 11003 (Teejet), ULD and ULD Max 12003 (Hypro), and MUG 11003 (Magnojet) were used to spray a tank mixture of 3.0 L c.p./ha of a soluble concentrate (SL) formulation of glyphosate potassium salt with 480 g a.e./L and 2.0 L c.p./ha of an SL formulation of a dicamba diglycolamine salt (480 g a.e./L) at 3 bar and 100 L/ha. Four solutions were prepared: the herbicides alone and mixed with polymer, guar, and modified seed oil adjuvants. All solutions with adjuvants also received 0.5% v/v of a volatility reduction adjuvant. A factorial experiment (four solutions × five nozzles) was set up with three replications. The droplet spectrum was analyzed by the volume median diameter (VMD), the percentage by volume of droplets smaller than 150 μm (V150), and the relative span using particle/droplet image analysis. There were significant interactions between nozzles and solutions for all experiments. The AIXR and ULD showed to be less advisable DRTs for dicamba plus glyphosate because they provided smaller VMD and higher V150 values. The interactions of the MUG and ULDM with the polymer adjuvant delivered droplets around 1,000 μm, so its use must be discussed according to the weed species and spray volume. Guar and polymer adjuvants produced higher values of VMD and lower values of V150 for most nozzles and were good DRTs for glyphosate plus dicamba. The TTI presented a good balance between VMD and V150 for all solutions and was a robust DRT for the herbicides.

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Response of Nebraska Horseweed (Conyza canadensis) Populations to Dicamba

Cited by 4 publications

References 13 publications

Differential Susceptibility of <i>Conyza bonariensis</i> Biotypes to Glyphosate and ALS-Inhibiting Herbicides in Argentina

Differential Susceptibility of <i>Conyza bonariensis</i> Biotypes to Glyphosate and ALS-Inhibiting Herbicides in Argentina

An integrated weed management strategy for the control of horseweed (Conyza canadensis)

Droplet Spectrum Generated by Air Induction Nozzles Spraying Solutions Containing Adjuvants and a Tank Mixture of Glyphosate and Dicamba

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Response of Nebraska Horseweed (Conyza canadensis) Populations to Dicamba

Cited by 4 publications

References 13 publications

Differential Susceptibility of &lt;i&gt;Conyza bonariensis&lt;/i&gt; Biotypes to Glyphosate and ALS-Inhibiting Herbicides in Argentina

Differential Susceptibility of &lt;i&gt;Conyza bonariensis&lt;/i&gt; Biotypes to Glyphosate and ALS-Inhibiting Herbicides in Argentina

An integrated weed management strategy for the control of horseweed (Conyza canadensis)

Droplet Spectrum Generated by Air Induction Nozzles Spraying Solutions Containing Adjuvants and a Tank Mixture of Glyphosate and Dicamba

Contact Info

Product

Resources

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Differential Susceptibility of <i>Conyza bonariensis</i> Biotypes to Glyphosate and ALS-Inhibiting Herbicides in Argentina

Differential Susceptibility of <i>Conyza bonariensis</i> Biotypes to Glyphosate and ALS-Inhibiting Herbicides in Argentina