Applications of Black Solider Fly (Hermetia illucens) Larvae Frass on Sweetpotato Slip Production, Mineral Content and Benefit-Cost Analysis
Round 1
Reviewer 1 Report
kindly find my comments:
1- Kindly describe the composition of non-selective agar plates And the production source.
2- As highlighted in text you write “all bacteria were” did you mean that after separating each colony or what?
3- Explain how the sample still contain Acetobacter sp., Pseudomonas sp., P. graminis, P. syringae, and P. pumonensis after drying at 100oC. Or what you mean? Explain in details?
4- Describe the one or more software you used.
5- Follow other comments with yellow color in the text and correct all.
Please find below manuscript with highlighted suggestions.
Comments for author File: 
Comments.pdf
Author Response
- Kindly describe the composition of non-selective agar plates And the production source.
Response: This has been stated now on lines 114. We made a mistake previously – the Heart Brain infusion agar was the non-selective agar (and only one) used to grow the bacteria
- As highlighted in text you write “all bacteria were” did you mean that after separating each colony or what?
Response: Yes, so all colony forming units (CFU) were collected and pooled – we did not identify and enumerate each CFU but rather wanted to see what bacteria were present.
- Explain how the sample still contain Acetobacter sp., Pseudomonas sp., P. graminis, P. syringae, and P. pumonensis after drying at 100oC. Or what you mean? Explain in details?
Response: yes, we were surprised to see this as many that were identified were not spore-forming that may have survived the heat treatment. As we wrote in the discussion, it may have been possible that the frass became contaminated prior to analysis – this could have been when the frass was hammer milled and/or during storage.
- Describe the one or more software you used.
Response: this has now been added (line 191-192).
5- Follow other comments with yellow color in the text and correct all.
Please find below manuscript with highlighted suggestions.
Response: we have corrected all. Thank you
Reviewer 2 Report
This MS is compact and sound, and the topic is of high interest due to increasing production of BSFL biomass. Abstract and introduction are clear and informative. Material and methods is well written and gave all relevant information about the study. However, use of chronological order could be advised for lines 142-144. Results are presented well but highlighting the most important or ones with the most interesting differences could be done by using figures. Maybe presenting Table 1. as figure and Fig. 1 as table. Discussion explains well the results found. Conclusions, however, is repeating them a bit. It would be nice to read more about possible risks related to use of frass (Pseudomonas) and considerations of usability of frass-fertilized soil after short slip production period as the nutrient are probably released slowly.
Author Response
We would like to sincerely thank the reviewer for their assessment of our manuscript and encouraging words. We have changed the chronological order in the materials and methods. In the conclusions, we touched on the potential implications of detecting a plant pathogen/probiotics and (as the reviewer rightly points out) that because organic fertilizers release nutrients more slowly, the possibility of having multiple harvests from one application might be a worthwhile research direction from an economic point of view.
Reviewer 3 Report
Good study, and interesting! Well done. One thing needs to be clarified (some minor spelling itemized follow below):
Table 5, the price for frass of $4.50/kg, how did you get this number? Did you purchase the frass from the supplier at the university? This is a critical number for the economic analysis in this paper, and the reader needs to know it is not a subsidized number, since the frass came from a university, not a business. This is what is in lines 83 to 86: "The BSFL frass was produced in the lab at University of Arkansas at Pine Bluff 83 (UAPB) and the larvae were cultured according to Fischer and Romano [22]. The substrate 84 used to feed the larvae were a combination of breads and fruits/vegetables. The frass 85 was collected after three weeks of vermicomposting and was oven dried (Despatch; LBB 86 Series 2-12-3) at 100C for 48 hours."
Since this is not a business, the reader either needs to know that this price is typical for the industry or that the $4.50/kg is an estimate of what the market price will be, or a university price, noting that the university is publicly subsidized and is not a business.
specific comments, by line
35 relative to what? just state, "high in"
37-38 either use the numbers for citations [4,5], or in text author, year (Dorper 37 et al. 2021; Kumar et al. 2021) but not both
38 will increase, not expand
58-59 are you writing about health benefit of sweet potatoes? Not sure why this is being mentioned, are you trying to convince the readers that they are good to eat? I suggest just stating that the roots and leaves are eaten.
60 storage roots is plural, so instead of it, should be they, or better yet, sweet potatoes
78 good statement of purpose
132 definition of treatments: control, 1 75.5 gm frass, 2 151 gm frass, tea
144 there are two spaces after the
165 166 again, either use the numbers for citations or in text, but not both in the same document
189 how economics calculated good
fig 1 and 2, ok, but top dressing 1 and 2 are not really helpful, the reader needs to go back to methods to understand this figure. Consider changing to 75.5 gm and 151 gm frass
278-295 why are there blank lines?
Author Response
We would like to sincerely thank you for your review and hope this version has been improved. Kindly find below for our point by point response to each comment. Thank you for your kind consideration,
Sincerely,
Nicholas Romano (on behalf of all co-authors)
Comment #1: Good study, and interesting! Well done. One thing needs to be clarified (some minor spelling itemized follow below):
Response to comment #1:
Comment #2: Table 5, the price for frass of $4.50/kg, how did you get this number? Did you purchase the frass from the supplier at the university? This is a critical number for the economic analysis in this paper, and the reader needs to know it is not a subsidized number, since the frass came from a university, not a business. This is what is in lines 83 to 86: "The BSFL frass was produced in the lab at University of Arkansas at Pine Bluff 83 (UAPB) and the larvae were cultured according to Fischer and Romano [22]. The substrate 84 used to feed the larvae were a combination of breads and fruits/vegetables. The frass 85 was collected after three weeks of vermicomposting and was oven dried (Despatch; LBB 86 Series 2-12-3) at 100C for 48 hours."
Since this is not a business, the reader either needs to know that this price is typical for the industry or that the $4.50/kg is an estimate of what the market price will be, or a university price, noting that the university is publicly subsidized and is not a business.
Response to comment #2: This is a great comment and something we should have addressed initially. We based this on examples we found online where companies were selling BSFL frass (which is more expensive than inorganic fertilizers based on weight). So this value is a reflection of typical market value, which we have included this. Kindly find below for some examples,
https://www.arbico-organics.com/product/black-soldier-fly-frass-fertilizer/Help-for-houseplants?gclid=CjwKCAjw9LSSBhBsEiwAKtf0nzVlgL4QN2kwufYfW_FIo66dVjoALitj0YK8KmPRd1DeZXKaDdxRkRoC0j8QAvD_BwE
https://hydrobuilder.com/organic-nutrients-insect-frass.html?opts=eyJhdHRyaWJ1dGUzNTQiOiIxMzY2In0=
https://www.happyhydro.com/products/gaia-green-super-fly-insect-frass?variant=39683496771651¤cy=USD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gclid=CjwKCAjw9LSSBhBsEiwAKtf0n76caMW2lbNtMlH60cl-er9jBm6VNVnVFC3Vmln3bv7FKahLx-3eixoCTfAQAvD_BwE
Comment #3: specific comments, by line 35 relative to what? just state, "high in"
Response to comment #3: this has been fixed.
Comment #4: 37-38 either use the numbers for citations [4,5], or in text author, year (Dorper 37 et al. 2021; Kumar et al. 2021) but not both
Response to comment #4: thank you for pointing this out, this has been fixed.
Comment #5: 38 will increase, not expand
Response to comment #5: this has been fixed.
Comment #6: 58-59 are you writing about health benefit of sweet potatoes? Not sure why this is being mentioned, are you trying to convince the readers that they are good to eat? I suggest just stating that the roots and leaves are eaten.
Response to comment #6: Point taken, we have removed this.
Comment #7: 60 storage roots is plural, so instead of it, should be they, or better yet, sweet potatoes
Response to comment #7: we have now used the term “sweetpotatoes” as “SPs” – in the abbreviated form
Comment #8: 78 good statement of purpose
Response to comment #8: Thank you!
Comment #9: 132 definition of treatments: control, 1 75.5 gm frass, 2 151 gm frass, tea
Response to comment #9: we have revised this hopefully according to suggestion
Comment #10: 144 there are two spaces after the
Response to comment #10: this area was revised
Comment #11: 165 166 again, either use the numbers for citations or in text, but not both in the same document
Response to comment #11: this has been fixed
Comment #12: 189 how economics calculated good
Response to comment #12: thank you
Comment #13: fig 1 and 2, ok, but top dressing 1 and 2 are not really helpful, the reader needs to go back to methods to understand this figure. Consider changing to 75.5 gm and 151 gm frass
Response to comment #13: Point well taken. We have changed this to 333 g/m2 and 667 g/m2 as this might provide even more information to the reader. Hope this is OK.
Comment #14: 278-295 why are there blank lines?
Response to comment #14: this has been fixed
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
