Effect of Plant Extracts and Metam Sodium on the Soilborne Fungal Pathogens, Meloidogyne spp., and Soil Microbial Community

Round 1

Reviewer 1 Report

I reviewed your paper : The potential efficacy of certain plant extracts and metam sodium in managing soil-borne fungal pathogens and Meloidogyne spp. and their effect on the soil microbial community.

I do believe your study is correctly designed and your objective clearly stated and respected throughout the paper.

I only have minor comments and most of them are about your methodology section. I do believe that there is an importan lack of information concerning the choice of your plant extracts.

Are they used actually?

Are they available in a commercialisable form?

On what did you base your choice for application doses ?

Why did you chose to combine LR to MS and not oanother plant extract?

Adding those details to your manuscript would improve the meaningness of it.

What about other plant extracts? Are there some studies that have shown their efficacity in controlling plant disease? This is missing from you introduction and your discussion.

In addition your conclusion is missing futur prospects or open questions...

I added all my comments in the attached file.

Comments for author File: Comments.pdf

Author Response

Please see the attachment

Author Response File: Author Response.doc

Reviewer 2 Report

Dear authors,

Your manuscript covered a relevant topic in agronomy. To test alternatives non-toxic to control pathogens and nematodes to contribute to sustainable agriculture is undoubtedly worthy of scientific interest. But this paper needs some improvements in order to clearly show the importance of the study and the results found. I strongly recommend that you, authors, rewrite the main idea of your study and conclusion in the abstract section. Unfortunately, that section did not provide a good summary of the research done. Below I also discuss some issues detected, ask for some clarifications and give some suggestions to improve this manuscript. Although the conclusions are consistent with the evidence and arguments presented, I suggest you sum up what you observed with your results in a conclusive way because the current conclusion seems a Results section instead. In general, I have to highlight that this paper is well written and easy to read.

Recommendations

Title: Effect of plant extracts and metan sodium on the soil-borne fungal pathogens,  Meloidogyne spp, and soil microbial community.

Keywords: Soil fumigation, plant extract, root-knot nematodes, pepper crop, 16S rRNA, ITS2, amplicon sequencing

For the NMDS and PERMANOVA analyses, I recommend that the authors use Bray-curtis dissimilarity instead of Euclidean distance. Also, unifrac distance is a useful metric for bacterial community analysis.

Results: In the first sentence, I think the authors wanted to say that the MS and LR+MS treatments showed higher pepper yields than the plant extract treatments without the addition of MS.

            Line 165: It would be more clear if you use “... for all treatments, except for LR+MS”.

Questions:

1. Could the authors explain why they used the metam sodium only once in the experiment while applying three times the plant extracts?
2. Please explain the criteria used to define the end of the experiment. Would it be the plant lifecycle?
3. 3.         The study design and materials are clearly laid out, but I could not understand why the authors had a treatment with a mixture of Larrea spp. and metam sodium, but they did not have a mixture of Liquidambar spp. and metam sodium treatment. Please explain this in Materials and Methods.
4. Why did the authors use the letter “a” to indicate the lowest values of  Gall index in figure 2? Please, also check figure 3. For other figures and tables, the letter “a” shows the higher mean values, which makes total sense.
5. Lines 218-219: Did the difference observe between the bacterial community structures in the MS and  LR+MS treatments at T1 and the other treatments based on the PERMANOVA? You should use PERMANOVA results to discuss differences, not NMDS.

Major concerns

Results: In the first paragraph, I agree that the root weight was significantly higher in both MS and LR+MS treatments, but I totally desagree that gall index was lower in LR+MS. If you check the results carefully, you can see there is no statistical difference for Gall index among LR+MS, LR and LQ treatments.

            Lines 171-172: Please include in this sentence “except for MS treatment”.

            Lines 191-192: For bacteria, I just saw a difference for Chao index between the control and MS treatments. Please review the Shannon results, the diversity differed between LR, and MS and LR+MS, only.

Minor concerns

Please include a reference from where we can find the recommendation of application doses used in this study.

Use italics for genus and species names.

Please avoid repeating terms in the same paragraph, such as ‘at the end of the experiment’ (1^st paragraph of Results section).

Figure 3: It is missing information about the letters and asterisks in bars.

Tables 1 and 2: Please include information about the values labeled with different uppercase letters.

Author Response

Please see the attachment

Author Response File: Author Response.doc