Phytotoxic Effects of Three Natural Compounds: Pelargonic Acid, Carvacrol, and Cinnamic Aldehyde, against Problematic Weeds in Mediterranean Crops

Round 1

Reviewer 1 Report

The paper entitled: `` Phytotoxic effects of three natural compounds: Pelargonic Acid, Carvacrol and Cinnamic Aldehyde, against problematic weeds in Mediterranean crops`` presents importance in the field of organic agriculture, in particular the weed control using bio pesticides.

Introduction

The theme is of interest, but the literature study does not focus on the topic addressed, presents general data and fewer aspects related to the subject.

The introduction is too extensive and I recommend to be restructured. The information presented in the first paragraphs (lines 33-63) is too general. I recommend synthesizing the information, reducing or reformulating it (e.g. lines 53-63). I consider that just the issues presented starting with line 75 relates strictly to the subject.

Considering that the study refers to weeds (Amaranthus retroflexus L., Portulaca olebercea L., Erigeron bonariensis L. and Avena fatua L.) control, the introduction isn`t properly structured and does not present a literature study regarding similar bio treatments applied to these seeds and induced effects.

The purpose of the work, presented in lines 87-95, should be included at the end of the introduction, in the last paragraph.

Materials and method

For all equipment used, for example, germination chamber, the manufacturer, locality and country of origin should be mentioned. The same approach is necessary for seed companies.

The author wrote: „the efficacy, that was defined as 0 if the plant was alive and 100 if the plant was dead, but it is not mentioned how the values are obtained: for example 73.5 were calculated or approximated? It is necessary to include the formula or explain the method of calculation, as well as the reference, if the method is adapted according to other authors.

Results

The results are detailed presented. Figures 5-8 must be redrawn in a clearer and suggestive graphic.

The study covers only the effect of bio pesticides on weeds, but it would have been useful to develop the research regarding the effect on some crop plants to see if it does not affect their development.

I consider that the lines 189-193 fit better in the introduction.

The same issues about how to determine and express the effectiveness of compounds is noted.

 

 

Author Response

Response to Reviewer 1 Comments

 

Thank you for your valuable time and your suggestions to improve our article.

 

Introduction

 

The theme is of interest, but the literature study does not focus on the topic addressed, presents general data and fewer aspects related to the subject.

The introduction was approached in this way because the article was for the special issue entitled “Physiological and Molecular Characterization of Crop Resistance to Abiotic Stresses” and the guest editors asked us, once the title was approved, to focus it considering the stress that weeds and herbicides cause on crops.

 

The introduction is too extensive and I recommend to be restructured. The information presented in the first paragraphs (lines 33-63) is too general. I recommend synthesizing the information, reducing or reformulating it (e.g. lines 53-63). I consider that just the issues presented starting with line 75 relates strictly to the subject.

The introduction has been rewritten, following the suggestions of the reviewer, synthesizing the information given until line 75.

 

Considering that the study refers to weeds (Amaranthus retroflexus L., Portulaca oleracea L., Erigeron bonariensis L. and Avena fatua L.) control, the introduction isn`t properly structured and does not present a literature study regarding similar bio treatments applied to these seeds and induced effects.

The introduction has been modified following the suggestions of the reviewer, now information about the weeds studied is presented, and an extensive revision of many works about natural products that have been used to control the weeds studied has been introduced.

 

The purpose of the work, presented in lines 87-95, should be included at the end of the introduction, in the last paragraph.

As suggested by the reviewer, the purpose of the work has been included at the end of the introduction.

 

Materials and method

For all equipment used, for example, germination chamber, the manufacturer, locality and country of origin should be mentioned. The same approach is necessary for seed companies.

We added the model, locality and country of origin for the plant growth chamber and the locality and country for the seed company Herbiseed. We also added this information for the data logger used to register the temperature and relative humidity data in the greenhouse.

 

The author wrote: „the efficacy, that was defined as 0 if the plant was alive and 100 if the plant was dead, but it is not mentioned how the values are obtained: for example 73.5 were calculated or approximated? It is necessary to include the formula or explain the method of calculation, as well as the reference, if the method is adapted according to other authors.

We rewrote the part of materials and methods describing how was valued the efficacy for a better understanding. The efficacy was scored for each plant as 0 if it was alive and 100 if it was dead, and then for each treatment, the efficacy was valued as the mean of the ten plants. The values as 73.5 and the other values reported in Table 5 were obtained when the multifactor analysis of variance was performed on efficacy including species, treatments, time after treatments application and their double significant interactions as effects. This values were calculated with the software Statgraphics Centurion XVII. We have the original data available if required.

 

Results

The results are detailed presented. Figures 5-8 must be redrawn in a clearer and suggestive graphic.

Figures 5 to 8 have been redrawn dividing them by natural product tested for a better comprehension. Now for each Figure there are A (for pelargonic acid), B (for cinnamaldehyde) and C (for carvacrol). We tried other types of graphic but as all treatments reach 100 efficacy in the majority of days line plots were worst because data could not be distinguished between treatments. If you have further suggestions for improve the Figures we will perform them.

 

The study covers only the effect of bio pesticides on weeds, but it would have been useful to develop the research regarding the effect on some crop plants to see if it does not affect their development.

This was the first study that we performed and we were trying to determine the active doses for different weeds, but still there is a lot of research to do, because we must define the doses-response curve for different weeds in order to know the optimum doses for each compound and also to study the effects in crops, and the phenological stage in which they should be applied to maximize herbicidal effect in weeds and minimize phytotoxic effects in crops. If the compounds would cause damage on crops they could be used to control weeds in inter-rows.

As suggested by the reviewer, in next steps we will study the effect of the tested products in crops.

 

I consider that the lines 189-193 fit better in the introduction.

Following the reviewer suggestion, we have move this text to the Introduction.

 

The same issues about how to determine and express the effectiveness of compounds is noted.

As explained above, the effectiveness of the compounds was calculated for each treatment (each doses tested of each compound) as the mean of the ten plants treated with each treatment. First, efficacy for each plant was valued (0 for alive plants and 100 for dead plants) and then the efficacy of the treatment was calculated as the mean of the efficacy for the ten plants treated. In materials and methods, we have introduced a more detailed explanation about how efficacy was calculated for each plant and for each treatment.

 

Reviewer 2 Report

I suggest to proceed to the publication in another section of the Journal: “Weed science and weed management” or “Farming sustainability”;

after correcting some parts,  including:

Row 108 /109

It is derived from rapeseed oil

It is derived from olec acid of different origin

Row 180

P ≤ 0.05 (should be corrected throughout the paper)

 

Tab 3 Max min

 

Fig 2 use only the initial for the name of the genus as shown in tab 3

 

figures from 5 to 8 are unclear

 

References

The bibliography is not complete

Author Response

Response to Reviewer 2 Comments

 

Thank you for your valuable time and your suggestions to improve our article.

 

I suggest to proceed to the publication in another section of the Journal: “Weed science and weed management” or “Farming sustainability”;

Thank you for the suggestion, we were sending the article for the special issue “Physiological and Molecular Characterization of Crop Resistance to Abiotic Stresses”, because they have approved the tittle of the Manuscript but when I was submitting the article I realized that “weed management” was not considered in this special issue, so for us is a good suggestion to send it to any of this other special issues, choose the one you consider our article suits better.

after correcting some parts, including:

 

Row 108 /109

It is derived from rapeseed oil

It is derived from oleic acid of different origin

Lines 108/109 have been corrected as suggested by the reviewer.

 

Row 180

P ≤ 0.05 (should be corrected throughout the paper)

It has been changed P˂0.05 for P ≤ 0.05 in all the paper, as suggested by the reviewer.

 

Tab 3 Max min

It has been changed in Table 3 Maximum and Minimum for their abbreviations Max. and Min.

 

Fig 2 use only the initial for the name of the genus as shown in tab 3

The names of the species have been written with the genus abbreviated as suggested by the reviewer in Figure 2 and also in Figure 3.

 

figures from 5 to 8 are unclear

Figures 5 to 8 have been redrawn dividing them by natural product tested for a better comprehension. Now for each Figure there are A (for pelargonic acid), B (for cinnamaldehyde) and C (for carvacrol).

 

References

The bibliography is not complete

We have added the DOI for references 22, 53 and 59, we did not found the DOI for reference 40.

We realized that references 47 and 53 were the same and we corrected it.

 

Round 2

Reviewer 1 Report

The author took into account the suggestions made. Since figures 5-6 are not explicit either in this form, I propose the redraw of the results in the form of a table.

Author Response

Response to Reviewer 1 Comments

 

Thank you very much for your valuable time and your suggestions to improve our article.

The author took into account the suggestions made. Since figures 5-6 are not explicit either in this form, I propose the redraw of the results in the form of a table.

We have prepared all the original data of Figures 5 to 8 as tables, but we think that it would be better to provide them as supplementary materials because the results are visually better represented in figures. We have uploaded a new file entitled Supplementary Materials with these tables.

Reviewer 2 Report

the work is interesting
small corrections should be made:

Row 349
Figure 4. Effect of the interaction between treatment and time after treatment in the efficacy.
  The caption does not exactly describe the contents of the figure

Row 406 Replace
Table 6. Damage level depending on the species, time after application and treatment

row 517:
Replace Da Mastro with De Mastro

Author Response

Response to Reviewer 2 Comments

 

Thank you very much for your valuable time and your suggestions to improve our article.

 

the work is interesting

small corrections should be made:

 

Row 349

Figure 4. Effect of the interaction between treatment and time after treatment in the efficacy.

The caption does not exactly describe the contents of the figure

We have rewritten the caption of Figure 4 for a more accurate description of the Figure.

 

Row 406 Replace

Table 6. Damage level depending on the species, time after application and treatment

We corrected the title of Table 6 as suggested by the reviewer.

 

row 517:

Replace Da Mastro with De Mastro

We corrected it as indicated by the reviewer.