The Addition of Saflufenacil to Glyphosate plus Dicamba Improves Glyphosate-Resistant Canada Fleabane (Erigeron canadensis L.) Control in Soybean

Round 1

Reviewer 1 Report

The manuscript ‘With Glyphosate plus Dicamba Applied Preplant for Glyphosate-Resistant Canada Fleabane (Erigeron canadensis L.) Control in Dicamba-Resistant Soybean, Will the Addition of a Third Tankmix Partner Improve the Level and Consistency of Control?’ deals with the control of GR Canada Fleabane through addition of third herbicide. The manuscript concludes that concludes that the level and consistency of GR Canada fleabane control was improved when saflufenacil was added to a PP application of glyphosate plus dicamba in soybean. The results are interesting, and be published in Agronomy after some necessary revisions. Following improvements are needed to bring the manuscript in publishable form.

• The title is little bit confusing, the second part of the title could be the title with some modifications. The current title is not attractive
• Can the classification of herbicides be given according to HRAC along with WSSA in introduction section?
• Table 4 unit of dose is incorrect
• The herbicide treatments are not explained well in MM. Please provide all details with reasons of selected doses
• The methods to compute recorded data are not sufficiently explained in MM. Please provide the detailed procedures to record and report the data
• The results are too numeric. The most of the numeric have been used to denote herbicide dose. Is it possible to give a Table in MM for treatments, give a code to each treatment and then use those codes afterwards?
• The results and discussion sections have been merged. Most of the section is results. The logics/reasons of the control should be provided
• Saflufenacil addition should be added in the title. May be addition of saflufenacil to glyphosate and dicamba improves the control over GR Canada Fleabane (Erigeron canadensis L.) Control in Dicamba-Resistant Soybean

The manuscript can be accepted after these changes

Author Response

Reviewer 1:

The manuscript ‘With Glyphosate plus Dicamba Applied Preplant for Glyphosate-Resistant Canada Fleabane (Erigeron canadensis L.) Control in Dicamba-Resistant Soybean, Will the Addition of a Third Tankmix Partner Improve the Level and Consistency of Control?’ deals with the control of GR Canada Fleabane through addition of third herbicide. The manuscript concludes that concludes that the level and consistency of GR Canada fleabane control was improved when saflufenacil was added to a PP application of glyphosate plus dicamba in soybean. The results are interesting, and be published in Agronomy after some necessary revisions. Following improvements are needed to bring the manuscript in publishable form.

• Thank you very much for your helpful review. I have made the following changes (listed in red).

• The title is little bit confusing, the second part of the title could be the title with some modifications. The current title is not attractive
• Changes made: Title changed to: The Addition of Saflufenacil to Glyphosate plus Dicamba Improves Glyphosate-Resistant Canada Fleabane (Erigeron canadensis L.) Control in Soybean.
• Can the classification of herbicides be given according to HRAC along with WSSA in introduction section?
• Changes made: Added HRAC Group O.
• Table 4 unit of dose is incorrect
• Changes made: Changed to g ai ha^-1.
• The herbicide treatments are not explained well in MM. Please provide all details with reasons of selected doses
• Changes made.
• Added: A list of all herbicide treatments in the experimental methods.  
• Added rationale for why the herbicides and the herbicide rates were used: ‘The herbicides were selected since they are commonly used to control GR Canada fleabane; the herbicides rates were selected based on the recommended field rates indicated on the label.’
• The methods to compute recorded data are not sufficiently explained in MM. Please provide the detailed procedures to record and report the data
• Changes made: Added more details to the Experimental Methods providing more detail about how the visual control ratings were conducted (i.e., % biomass reduction of the weedy control, recorded data in a notebook and logged it into ARM Software), and how the herbicides and the herbicide rates were selected.
• Changes made: Added more details to the Statistical Analysis speaking on why the transformations were used, the original form of the data was presented not the transformed form, and how significance is denoted in Table 4.
• The results are too numeric. The most of the numeric have been used to denote herbicide dose. Is it possible to give a Table in MM for treatments, give a code to each treatment and then use those codes afterwards?
• Thank you for this suggestion, I agree that there are quite a few numbers listed. I did not make changes because most of the rates in parentheses are from herbicide treatments used in supporting literature. If I made a table with these rates from referenced studies it may confuse the reader into thinking that these were rates or treatments used in the current study, which is not the case.
• The results and discussion sections have been merged. Most of the section is results. The logics/reasons of the control should be provided
• Changes made: Added a paragraph at the end that explains the two-way tankmix of glyphosate + dicamba provided a high level of control of its own so it was difficult to detect improvements in control from the addition of a third herbicide. But mentioned that it is beneficial to add a third herbicide into the tank to decrease the selection pressure for the evolution of herbicide resistance.
• Saflufenacil addition should be added in the title. May be addition of saflufenacil to glyphosate and dicamba improves the control over GR Canada Fleabane (Erigeron canadensis L.) Control in Dicamba-Resistant Soybean
• Changes made. Title changed to: The Addition of Saflufenacil to Glyphosate plus Dicamba Improves Glyphosate-Resistant Canada Fleabane (Erigeron canadensis L.) Control in Soybean.

The manuscript can be accepted after these changes

Reviewer 2 Report

This article aimed to determine a mixture of tiafenacil, metribuzin, bromoxynil, pyraflufen-ethyl/2,4-D, 2,4-D ester, halauxifen-methyl or saflufenacil to glyphosate plus dicamba applied PP, if they will improve the level and consistency of GDR Canada fleabane control in soybean.  Canada fleabane (Erigeron canadensis L.) is considered as a weed caused an important issue in the field but, there is no specific strategies to control this weed.

To control this weed the authors reveal in this study a mixture of tiafenacil, metribuzin, bro-moxynil, pyraflufen-ethyl/2,4-D, 2,4-D ester, halauxifen-methyl or saflufenacil to glyphosate plus dicamba applied PP.

This article is well organized in all different parts. The results of this article will add information to agronomy and will help scientists in agriculture to continue with the synergistic action of this mixture.

On the other side, the title is very long and is not impressive, I would like to suggest the authors modify the title.

  I would recommend this paper for publication after rectification in the title.

Author Response

Reviewer 2:

This article aimed to determine a mixture of tiafenacil, metribuzin, bromoxynil, pyraflufen-ethyl/2,4-D, 2,4-D ester, halauxifen-methyl or saflufenacil to glyphosate plus dicamba applied PP, if they will improve the level and consistency of GDR Canada fleabane control in soybean.  Canada fleabane (Erigeron canadensis L.) is considered as a weed caused an important issue in the field but, there is no specific strategies to control this weed.

To control this weed the authors reveal in this study a mixture of tiafenacil, metribuzin, bro-moxynil, pyraflufen-ethyl/2,4-D, 2,4-D ester, halauxifen-methyl or saflufenacil to glyphosate plus dicamba applied PP.

This article is well organized in all different parts. The results of this article will add information to agronomy and will help scientists in agriculture to continue with the synergistic action of this mixture.

• Thank you very much for your helpful review. I have made the following changes (listed in red).

On the other side, the title is very long and is not impressive, I would like to suggest the authors modify the title.

• Changes made. Title changed to: The Addition of Saflufenacil to Glyphosate plus Dicamba Improves Glyphosate-Resistant Canada Fleabane (Erigeron canadensis L.) Control in Soybean.

  I would recommend this paper for publication after rectification in the title.

Reviewer 3 Report

Agronomy is an international and cross-disciplinary scholarly journal on agronomy and agroecology. It publishes reviews, regular research papers, communications and short notes. The aim is to encourage scientists to publish their experimental and theoretical research in as much detail as possible. Full experimental and/or methodical details must be provided for research articles.

 

According to the above, I cannot recommend the publication of this paper entitled

With Glyphosate plus Dicamba Applied Preplant for Glyphosate-Resistant Canada Fleabane (Erigeron canadensis L.) Control in Dicamba-Resistant Soybean, Will the Addition of a Third Tankmix Partner Improve the Level and Consistency of Control?

 

The paper is mere testing without only scientific interest except for farmers and advisors living in the particular region. Consequently, the results are not helpful and of general interest for the International audience of the journal Agriculture.

The four field trials over two years are well designed and analyzed according to well-established theory. Nevertheless, the use of only one rate of the various herbicides and combinations hereof does no further our understanding of what to do with the glyphosate-resistant Erigeron canadensis.

There is no explanation why the various herbicides were selected in the special rates, let alone the mode of action of their various compounds.

The soybean yields were not affected except for the weedy control .and the weed-free control. (Table 4). Likewise, there were no differences among the various combinations of herbicides, be it control at various weeks after herbicide application, plant density, and biomass of the weeds.

 

Consequently, I'm afraid I have to disagree with the conclusions

 

 “…This study concludes that the level and consistency of GR Canada fleabane control was improved when saflufenacil was added to a PP application of glyphosate plus dicamba in soybean.”

 

 

Author Response

Reviewer 3:

Agronomy is an international and cross-disciplinary scholarly journal on agronomy and agroecology. It publishes reviews, regular research papers, communications and short notes. The aim is to encourage scientists to publish their experimental and theoretical research in as much detail as possible. Full experimental and/or methodical details must be provided for research articles.

• Thank you for your review. I went through the manuscript and tried to include thorough detail regarding the experimental and statistical methods. I hope the additions make it more clear of the importance of this research. Specifically, I think the use of a 3-way tankmix to control GR Canada fleabane is valuable to soybean growers worldwide since it provides additional effective chemical options for these growers and more importantly, it re-iterates the importance of resistance management (by adding an effective third herbicide into the tank).

According to the above, I cannot recommend the publication of this paper entitled: With Glyphosate plus Dicamba Applied Preplant for Glyphosate-Resistant Canada Fleabane (Erigeron canadensis L.) Control in Dicamba-Resistant Soybean, Will the Addition of a Third Tankmix Partner Improve the Level and Consistency of Control?

The paper is mere testing without only scientific interest except for farmers and advisors living in the particular region. Consequently, the results are not helpful and of general interest for the International audience of the journal Agriculture.

The four field trials over two years are well designed and analyzed according to well-established theory. Nevertheless, the use of only one rate of the various herbicides and combinations hereof does no further our understanding of what to do with the glyphosate-resistant Erigeron canadensis.

• Only one rate of each herbicide was used since the rates selected were based on recommended field rates indicated on each herbicide label.
• Glyphosate/dicamba resistant soybean coupled with the use of dicamba-based products is a strategy farmers can use to control glyphosate-resistant weeds. Though, this research indicates that the level of GR Canada fleabane control may not be immensely improved with 3-way tankmixtures it re-iterates the importance of adding multiple effective modes of action into the tank with dicamba in order to mitigate the evolution of resistance to further effective modes.

There is no explanation why the various herbicides were selected in the special rates, let alone the mode of action of their various compounds.

• Changes made:
• Added on page 3: ’The herbicides were selected since they are commonly used to control GR Canada fleabane; the herbicide rates were selected based on the recommended field rates indicated on the label.’
• Added on page 4/ Table 3: The mode of action of each herbicide.

The soybean yields were not affected except for the weedy control and the weed-free control. (Table 4). Likewise, there were no differences among the various combinations of herbicides, be it control at various weeks after herbicide application, plant density, and biomass of the weeds.

• The addition of saflufenacil to glyphosate + dicamba resulted in a significant increase in control of 57 to 92, 93 to 99, and 94 to 99% at 2, 4, and 8 WAA respectively relative to glyphosate + dicamba (near perfect control at 4 and 8 WAA). It was also the treatment that provided the most consistent control.
  • The addition of saflufenacil as the third herbicide in the tank also provided the greatest level and had the quickest activity on GR Canada fleabane at 2 WAA.

Consequently, I'm afraid I have to disagree with the conclusions

 “…This study concludes that the level and consistency of GR Canada fleabane control was improved when saflufenacil was added to a PP application of glyphosate plus dicamba in soybean.”

• Changes made: Re-wrote the conclusion paragraph to focus on saflufenacil + glyphosate + dicamba providing…
  • The highest level and most consistent GR Canada fleabane control at 2, 4, and 8 WAA.
  • Highlighted the importance of adding a third effective herbicide into the tank (such as saflufenacil) to prevent the onset of herbicide resistance. Resistance management is extremely important due to the rise in resistant weed species worldwide.
  • Highlighted the fast early season GR Canada fleabane control reported at 2 WAA with this three-way tankmix.

Round 2

Reviewer 1 Report

I have gone through the revised version of the manuscript where all comments of mine have been properly addressed. Therefore, the manuscript can be accepted in the current form.

Reviewer 3 Report

I cannot still warrant the publication of this paper entitled: With Glyphosate plus Dicamba Applied Preplant for Glyphosate-Resistant Canada Fleabane (Erigeron canadensis L.) Control in Dicamba-Resistant Soybean, Will the Addition of a Third Tankmix Partner Improve the Level and Consistency of Control?

Whatever changes you have made, the paper tests spray mixes in one dose combination. There are no effect differences, and the research question you want to test shows no effect of the various sprays.

To make my point clear, look at the keywords you use:

Keywords: Additive; antagonistic; biomass; density; synergy; weed control; grain yield

Neither additive, antagonistic, nor synergy has been defined elsewhere, let alone connected to the non-significant results. The words have been used once in the keywords to catch interest.

I suggest it should be rejected without any resubmission