Overall

The study design was appropriate to answer the aim highlighted by the researcher. The study provided an update on the currently available cultivars in Brazil and their tolerance levels to sugarcane borer feeding. The downfall of this paper is that the study was conducted under greenhouse conditions and these results may not reflect the natural occurrence or behavior of the pest.

Overall statement

The article provided useful data on the tolerance level of key sugarcane cultivars in Brazil. This is basically new information since most information on cultivar tolerance in the country was done on cultivars that are no longer planted. The research observed three cultivars that showed resistance to sugarcane borer. Cultivars IACSP96-2101 and IACSP96-2042 were the least preferred cultivars for oviposition while cultivar IACSP94-2094 was the least preferred for sugarcane borer entry and development.

Overall strengths of the article

The article provided useful current data in the field of sugarcane borer IPM. The data provided allows for a new approach in the management of sugarcane stalk borer. The most used method of control is biological control. In areas where borer population is very high the introduction of a tolerant variety can help reduce damage levels.

Major points in the article which needs clarification and suggestions include: 1. Since the authors used the same canes for the oviposition and antibiosis analysis it should be clear how the author ensured eggs from the oviposition test did not affect the results of the antibiosis analysis. 2. The authors should ensure that confidence or p-value is mentioned when indicating significant results. 3. The authors should support the claim that states that there is no correlation between trichomes on leaves and oviposition of the sugarcane borer moths.

Other minor points that should be addressed include: 1. Page 4 line 8 change others to other. 2. Since the egg clusters are quantifiable the author should state “number of egg clusters” instead of “amount of egg cluster”

Comments on abstract, title, references

Abstract The authors did not provide sufficient background information on the importance of assessing cultivar resistance to Diatraea saccharalis. Hence the context of the study was not highlighted. However, the authors did give a clear and concise objective to highlight the knowledge gap. Despite this, the authors were not specific enough to state where the study was done since different countries tend to develop different sugarcane cultivars for their specific geographical location. The methodology used for both oviposition preference and larval development was clearly mentioned by the author in the abstract. The major results from both the oviposition preference and larval development test were also provided. However, there was no statistical value to support the key findings. Nonetheless, the abstract, however, ended on the key outcome that satisfied the stated objective. The title outlined by the authors contains the main features of the article and those outlined in the abstract. The title is an accurate representation of the paper. However, the title did not mention where the study was conducted. Since sugarcane cultivars vary with the country, the location should be clearly stated in the title. The cultivars used in this study would not be found in another country with a sugarcane breeding program. The references cited for the paper appear to be current, relevant and are the major references about the topic. The references are cited correctly for the paper. The keywords used by the author was able to accurately reflect the content of the paper, however the author could have included “cultivar resistance” as a keyword.

Comments on introduction/background

The opening statement of the introduction can be supported with more than one reference since research done on Diatraea saccharalis is vast. The statement made on the secondary pest Metamasius hemipterus can be omitted from the introduction since the occurrence of this pest after sugarcane borer damage is not common. This may be replaced with a definition for insect resistance and the factors that helps to contribute to insect resistance in sugarcane cultivars. The addition of the percentage losses in the paper helped to highlight the importance of minimizing sugarcane borer pest damage. This was a very good way of ending the background information section of the introduction and transitioning into the importance section. The authors highlighted that data of susceptibility of currently grown sugarcane cultivars to D. saccharalis are limited. This was important to highlight the knowledge gap on the subject matter. The authors proceeded to indicate that most of the data available are for cultivars that are no longer planted. This is important since sugarcane breeding programs are continuously developing new cultivars. The authors, however, did a good job at highlighting the limitation of recent works on currently planted cultivars. This led to justification and importance of the current study. The purpose of the paper was clearly highlighted. The author ended by mentioning the two major objectives of the paper.

Comments on methodology

For the oviposition preference test, the variables were correctly identified. However, the method of measurement used was too subjective. What basis did the authors use to classify an egg cluster as small, intermediate, or large? The authors should provide an egg range for each cluster classification. Also, how were the 60 eggs used for classification determination selected from the different plants? Did the method involve selection of eggs from each cultivar? The authors should make mention of this. In terms of the antibiosis analysis, the variables were again correctly identified. The measurement method used is accepted and widely used when assessing sugarcane borer damage is sugarcane. The authors, however, appeared to use the same plots from the oviposition test. The oviposition test relied on the moth released in the greenhouse natural’s ability to oviposit eggs. However, for the antibiosis analysis, the authors artificially infested each plot. How did the author ensure that eggs from the previously conducted oviposition test did not remain for the antibiosis test? That should be clearly stated in the methodology. Both oviposition tests and the antibiosis analysis used by the author to assess the cultivars for resistance/susceptibility to Diatraea saccharalis are valid. However, the reliability of the antibiosis analysis is slightly compromised since it was done using the same plots after the oviposition test was concluded. Overall, the details provided in the methodology were enough to allow reproducibility of the study. The author provided a detailed set up of the planting of the plots and the set-up of the randomized block design. The author did not use negative controls due the nature of the study, however, the author included a single variety that was referred as the standard. The standard used is SP91-115 and was selected because it is susceptible to the borer and widely grown in the Sao Paulo area where the study was conducted. In terms on the variety selection, the authors can include why each variety was selected for this trial (eg. percentage distribution). The authors can also provide some morphological description of each variety in a table format (eg. presence of trichomes, rind colour etc.). Release timings were mentioned and timing for data collection was also mentioned .

Comments on data and results

The oviposition test data (Table 1) were presented in a table format. The table was hard to read at first glance but after reading the supported text it became clearer. The authors used the Tukey test at 10% probability for all the analyses throughout the paper. The table contained appropriate rounding, units and number of decimals. It was correctly labelled and the categories grouped appropriately. As mentioned before, the text helped to support the table presented and made it easier to understand. The authors did a good job of highlighting the meaningful results from the analysis. The authors focused mainly on cultivars that reported a lower number of egg clusters. The most infested cultivar was only mentioned once. Both the highly infested and the least infested cultivars are important to mention in resistance studies like this. The antibiosis analysis used three tables (Tables 2, 3 and 4). All three tables were presented with appropriate units, rounding and number of decimals. The titles were clear and detailed. The supporting texts for all the tables were able to bring out the meaningful results. The authors mentioned throughout the text that a significant difference was found between observed cultivars however in the text they did not make mention of a p-value. In the table, however, the observed significant difference was properly highlighted.

Comments on discussion and conclusions

The author merged both the results and discussion sections. The discussion for the oviposition test saw the authors citing various similar studies and obtained similar results. The authors alluded to the reduced oviposition on sugarcane cultivars may be due to the presence of trichomes on the leaves. The authors cited various studies done with corn to support this claim. Despite this, only one cultivar that had low oviposition rate had trichomes present on the leaves. The authors also made a claim that there was no correlation between the presence of trichomes and the number of eggs laid. The authors should use evidence to support this claim . The authors were able to draw sound conclusions from the oviposition tests that two of the 10 cultivars showed resistance to sugarcane stalk borer damage. In the antibiosis analysis, the authors used various angles to explain their findings. They indicated that previous results that showed where trichomes would inhibit the development of larvae. Since this was not observed in their study, their observations were attributed to the presence of exciting substances and suppressant substances. There were no references to support this and perhaps the authors can mention that this is an avenue for future study. The authors concluded that one cultivar appeared to be resistant after the conclusion of the antibiosis analysis. The cultivar, however, was not one of the two cultivars named from the oviposition test. Overall, the authors did a good job at citing references that had similar results and explanation. The authors referred to fast and slow growing cultivars and the effect it has on cultivar resistance to sugarcane borer. This was mentioned for the first time in the paper. This was out of the scope of the research. This points to results that the author may have observed during the project execution. The authors should have mentioned this in the introduction and the objectives. In summary, there are a few limitations that were evident from the discussion. This includes the effects of trichomes and the development of sugarcane borer larvae. The limitation opens the avenue for future work on the subject matter. The authors may also state what will be done with the cultivars studied and the way forward. The authors may also include how doing future works (incorporating other factors that affect cultivar resistance) can help to confirm the results resented. Nonetheless, as a breeding program continues to develop new cultivars the information presented add values to the area of knowledge.