Efficiency of Schinus molle Essential Oil against Bactericera cockerelli (Hemiptera: Triozidae) and Sitophilus zeamais (Coleoptera: Dryophthoridae)
Round 1
Reviewer 1 Report
Secondary metabolites of plants play important role in plant defense against insect pests. Essential oils from non-hostplants often show toxicity, repellency and anti-feeding effect on pest. In this study, essential oil was extracted from an important South America native aromatic plant species, Schinus molle, and the volatile compounds were identified. Schinus molle oil was then tested in a range of concentrations for the toxicity on late instar nymphs of tomato/potato psyllid and adults of maize weevil. The lethal concentrations of the oil on the 2 important pest species (LC) were calculated. Moreover, repellency effect of this oil on the weevil adults was also determined. The results and findings are very significant.
Comment:
- In addition to toxicity, plant essential oil often shows repellency or anti-feeding effect on insect pests. In the experiment design, it might be better if the study just focus on 1 pest species, but cover the whole possible stages (egg, nymph/larva and adult), and test for all possible insecticidal effect (toxicity, repellency or anti-feeding activity).
- Table 4, the difference of the weevil number between treated and untreated grain can be compared with t If it is not significant, there will not be repellency effect to the weevil adult.
Author Response
Suggested changes have been introduced in the manuscript accordingly (see the text in red color). We thank the reviewer for this valuable criticism, and we are taking action for future projects to improve the way we present our papers.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
These are my main comments on the manuscript (Agriculture-1643016) entitled “Efficiency of Schinus molle essential oil insecticidal agents against two economic importance crops pests: Bactericera cockerelli (Hemiptera: Triozidae) and Sitophilus zeamais (Coleoptera: Dryophthoridae)”. The manuscript examines the potential of Schinus molle essential oil, and its effect on two economic importance crops pests. The study reveals for the first time the essential oil insecticidal effect on the fourth and fifth nymphal stage of B. cockerelli and repellency activity against S. zeamais. Following substantial revisions should be incorporated in the manuscript.
- I have concerns about the introduction section of the paper that I believe need to be addressed in order to improve its clarity.
- Retention index for each chemical compound and chromatogram is needed.
- In results, information probit analyses are missing (X2-value, slope, and p-value).
- Manuscript is very extensive and repetitive, should be more concise in all lines.
- Other revisions could be checked in PDF attached.
Comments for author File: Comments.pdf
Author Response
Suggested changes have been introduced in the manuscript accordingly (see the text in red color). We thank the reviewer for this valuable criticism, and we are taking action for future projects to improve the way we present our papers.
Author Response File: Author Response.pdf
Reviewer 3 Report
Line 30-31
A large number of pests have disturbed agriculture crop yield. This study aimed to deter- 30 mine the chemical composition of Schinus molle essential oil, and its effect on two economic im- 31 portance crops pests (Bactericera cockerelli immature stage and Sitophilus zeamais adults).
The abstract need improvement. A large number of pests have disturbed agriculture crop yield. This sentence needs to change should make proper meaning. You must start with importance and botanical pesticides as you are representing a botanical pesticides as ecofriendly and novel alternatives to synthetic chemicals.
Line 54-55
Similar work on toxicity of essential oils against Asian citrus psyllid has been published by Rizvi et all 2018. You can take information from that manuscript. Specially the abstract.
185-186
essential oil in 70% ethanol. I think the oil in ethanol when applied to leaves will form drops and insects get space to eat. Usually, we add some surfactants to avoid this issue. Does this experiment you use some surfactant?
Line 255
Table 1. Compounds obtained from Schinus molle dried leaves essential oil analyzed by GC–MS.
The literature KI is missing.
Line 245
The yield of essential oil is missing. What was the yield of essenatil oil from S. mole.
Line
312-313 Plants produce a vast array of natural products (secondary metabolites). These com- 312 pounds have important ecological functions, protecting against pests [74, 75]. This sentence is little confusing need to rewrite.
What are the possible mode of action of toxicity, you can find some information from Rizvi et all 2018 and Pavella et all 2021. You can take information from that manuscript.
Conclusion
What is the future perspective of this study? I.e. essential oil nono formulation etc. Mostly essential oils are volatile in nature it needs some encapsulation of nano formaultion for broader application?
Author Response
Suggested changes have been introduced in the manuscript accordingly (see the text in red color). We thank the reviewer for this valuable criticism, and we are taking action for future projects to improve the way we present our papers.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors have incorporated all suggestions and comments into the revised version, now the manuscript seems much clear. There are some minor points to be corrected:
Ls.29-30: Revise this sentence to eliminate rewordiness.
Ls.33-34: …were: o-Cymene (29.04%), 1R-α-Pinene (15.52%), camphene (14.00%), and β-myrcene (11.54%).
L.139-141: Revise this sentence to eliminate rewordiness.
L.230-232: Sentence starting “The Student t-test was used to compare significant differences between…”
L.278: Delete “Each day the lethal concentration (LC) was obtained by Probit analysis.”
Table 3: In LC90, the values “864.29 ± 45.09(657.51 - 799.27” for 48 h fifth instar are incorrect. Revise.
L.299: Delete “Each day, the lethal concentration (LC) was calculated using Probit analysis.”
L.337: Change “Beta-caryophyllene” to “β-caryophyllene”
L.350: …Xantogaleruca luteola Müller (Coleoptera: Chrysomelidae)… Please, provide the ID author for all insect species mentioned in all manuscript.
Ls.421-423: …on fourth and fifth instar nymphs of B. cockerelli S. zeamais adults.
Author Response
Suggested changes have been introduced in the manuscript accordingly (see red text with yellow shading)
We thank the reviewer for this valuable criticism, and we are taking action for future projects to improve the way we present our papers.
Author Response File: Author Response.pdf
