World’s Best Practice Locust and Grasshopper Management: Accurate Forecasting and Early Intervention Treatments Using Reduced Chemical Pesticide

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

 

Review World’s Best Practice Locust and Grasshopper Management: accurate forecasting and early intervention treatments using reduced chemical pesticide

 

First, I had to mention, that the paper is of high interest, and the topic have economic and scientific value.

Only some minor problems has to be solved before publication.

1.     Please verify the references in text, some are numbered, others are with authors and years.

2.     There are spaces in text (Abstract) that needs to be deleted.

3.     I cannot understand figure 1, please change or add some more explanations. It seems as a dessert sandstorm picture.

4.     In general, I would like to see more pictures about locusts and grasshoppers damages eventually presenting these separately from each other.

5.     The figure 2 is also needs some clarifications, eventually by using a magnifying glass function in Photoshop, one better and closer view about damages could be projected on this picture.

6.      Finally, I would like to see, and it would help understanding the management methods, if a table would combine all active ingredients and bio pesticides or funguses used for protection against locusts and grasshoppers.

 

Author Response

First, I had to mention, that the paper is of high interest, and the topic have economic and scientific
value. Only some minor problems has to be solved before publication.
1. Please verify the references in text, some are numbered, others are with authors and years.
Author’s reply: All of the references are numbers. Name and date are only after species names as in
line 51 for Schistocerca cancellata (Serville, 1838) which is the correct taxonomic way of naming a
species.
2. There are spaces in text (Abstract) that needs to be deleted.
Author’s reply: these spaces were not in original document but appeared in the pdf version: Have
corrected on revised version.
3. I cannot understand figure 1, please change or add some more explanations. It seems as a dessert
sandstorm picture.
I have added arrows pointing to the dark band front and eaten out areas to make what is seen clearer.
4. In general, I would like to see more pictures about locusts and grasshoppers damages eventually
presenting these separately from each other.
I added two examples of damage: Locust swarm in Argentina and Locusta band damage in Australia.
5. The figure 2 is also needs some clarifications, eventually by using a magnifying glass function in
Photoshop, one better and closer view about damages could be projected on this picture.
I tried expanding but the expanded area is quite fuzzy as the photo is of too low a resolution.
However, the brown colour of the photo are clearly not leaves of the tree but something else—locusts!
6. Finally, I would like to see, and it would help understanding the management methods, if a table
would combine all active ingredients and bio pesticides or funguses used for protection against
locusts and grasshoppers.
Table added listing commonly used biopesticides for locust and grasshopper management.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript “World's Best Practice Locust and Grasshopper Management: accurate forecasting and early intervention treatments using reduced chemical pesticide" (author David Hunter) is a useful work that deserves publication. The author of this MS has a very rich experience of working with locusts, which he shares with readers, although at the same time a very small part of the literature on locust population management is cited in the review. As a result, when reading the MS, a number of questions arise, some of which seem really important. So, it is well known that phytosanitary forecasts are divided into short-term, medium-term and long-term. In the MS, in fact, we are talking only about short-term (and to a lesser extent medium-term) forecasts, and when talking about long-term ones, the problem boils down to the issue of money shortage, namely: “While financial support at some level for such international cooperation can be ensured for species that have frequent outbreaks, continuing financial support has often proved to be very difficult for species that have sporadic outbreaks: during the long periods between outbreaks there are other more pressing immediate financial priorities…” But here one could speculate about the development of long-term forecasts based, among other things, on the cyclical nature of solar activity, especially since a recent article was devoted to this issue in the Agronomy: Cheke, R. A., Young, S., Wang, X., Tratalos, J. A., Tang, S., Cressman, K. Evidence for a causal relationship between the solar cycle and locust abundance. Agronomy 2020, 11, 69. Of course, the “solar“ forecasts of acridid’s breeding outbreaks does not always work everywhere, but such an analysis would be very useful if we keep in mind the World's Best Practice. Of the other small disadvantages of the review, we note an uncritical discussion about the advantages of Ultra Low Volume spraying (“While the more readily available water-based sprays are still commonly used, vehicle mounted or aerial Ultra Low Volume (ULV) spraying is becoming the method of choice [26]. ULV spraying allows for more exact control of the droplet spectrum so that there is less waste from very small droplets that drift away, or from very large droplets that can contain much more than a lethal dose and often miss the target locusts and vegetation, as droplets fall rapidly to the ground especially when vegetation is sparse”). Indeed, world practice shows that the advantages of Ultra Low Volume spraying should be spoken with caution, because this technique has some negative side effects (the possibility of severe droplet drift, their evaporation, increased requirements for water quality, higher cost of equipment). And finally, the conclusion of the MS does not contain special emphasizing the need to expand work in the field of biopesticides against locusts and grasshoppers.

Author Response

Reviewer 2: The manuscript “World's Best Practice Locust and Grasshopper Management: accurate forecasting and early intervention treatments using reduced chemical pesticide" (author David Hunter) is a useful work that deserves publication. The author of this MS has a very rich experience of working with locusts, which he shares with readers, although at the same time a very small part of the literature on locust population management is cited in the review. As a result, when reading the MS, a number of questions arise, some of which seem really important. So, it is well known that phytosanitary forecasts are divided into short-term, medium-term and long-term. In the MS, in fact, we are talking only about short-term (and to a lesser extent medium-term) forecasts, and when talking about long-term ones, the problem boils down to the issue of money shortage, namely: “While financial support at some level for such international cooperation can be ensured for species that have frequent outbreaks, continuing financial support has often proved to be very difficult for species that have sporadic outbreaks: during the long periods between outbreaks there are other more pressing immediate financial priorities…” But here one could speculate about the development of long-term forecasts based, among other things, on the cyclical nature of solar activity, especially since a recent article was devoted to this issue in the Agronomy: Cheke, R. A., Young, S., Wang, X., Tratalos, J. A., Tang, S., Cressman, K. Evidence for a causal relationship between the solar cycle and locust abundance. Agronomy2020, 11, 69. Of course, the “solar“ forecasts of acridid’s breeding outbreaks does not always work everywhere, but such an analysis would be very useful if we keep in mind the World's Best Practice. Of the other small disadvantages of the review, we note an uncritical discussion about the advantages of Ultra Low Volume spraying (“While the more readily available water-based sprays are still commonly used, vehicle mounted or aerial Ultra Low Volume (ULV) spraying is becoming the method of choice [26]. ULV spraying allows for more exact control of the droplet spectrum so that there is less waste from very small droplets that drift away, or from very large droplets that can contain much more than a lethal dose and often miss the target locusts and vegetation, as droplets fall rapidly to the ground especially when vegetation is sparse”). Indeed, world practice shows that the advantages of Ultra Low Volume spraying should be spoken with caution, because this technique has some negative side effects (the possibility of severe droplet drift, their evaporation, increased requirements for water quality, higher cost of equipment). And finally, the conclusion of the MS does not contain special emphasizing the need to expand work in the field of biopesticides against locusts and grasshoppers.

To me, the longer-term forecasts based on solar cycles are too speculative to include as part of World’s Best Practice. And with climate change such correlations may become less and less relevant.

I have revised ULV at end of section 4.1 mentioning limitations.

I have added a sentence at end of section 4.4 on biopesticides emphasizing the importance of further research on their implementation.

The conclusions have been expanded significantly as per the third reviewer’s suggestions, including an emphasis on research needed in many areas if preventive management is to continue and expand in the face of restrictions on chemical pesticide use and climate change.

Reviewer 3 Report

Comments and Suggestions for Authors

General comment

The manuscript you provided focuses on the best practices in locust and grasshopper management, emphasizing early intervention and the use of reduced chemical pesticides. The manuscript provides a broad perspective on global strategies for managing locusts and grasshoppers, effectively integrating various methodologies such as chemical control, biopesticides, and forecasting systems. The structure of the paper is easy to follow, covering key areas like preventive management, chemical pesticide reduction, biopesticide use, and forecasting. The emphasis on strip spraying and the increasing adoption of biopesticides represents a forward-looking approach to pest management, addressing both environmental and economic concerns. The inclusion of international examples, such as from Australia, Africa, and China, broadens the paper’s relevance to global audiences.

Overall, this manuscript offers a robust examination of current locust and grasshopper management techniques, but it would benefit from deeper technical discussions and expanded literature on some of the strategies it advocates for, especially in regard to biopesticides and forecasting.

 

Specific Comments and Suggestions for Revisions

1. Abstract (Lines 8-26)

Comment: The abstract provides a broad overview of the main topics, but it lacks specific quantitative or qualitative results from the discussed methodologies. It should briefly mention the effectiveness of techniques such as biopesticides and strip spraying.

 

Suggestion: Add a sentence that summarizes the key findings or results from biopesticide use or forecasting systems, such as "Biopesticides were found to reduce pesticide application by X%, with a Y% reduction in non-target species impacts."

 

2. Introduction (Lines 29-65)

Comment: The introduction effectively sets up the problem, but there is no direct mention of climate change, which is a significant factor in locust and grasshopper outbreaks. Climate variability could be better integrated into the scope of the problem.

 

Suggestion: Include a brief mention of how climate change exacerbates locust outbreaks, with references to recent research. For example, "Climate change, particularly increasing variability in rainfall, has been linked to more frequent and severe locust outbreaks (Author et al., 2021)."

 

3. Preventive Management (Lines 90-108)

Comment: The section on preventive management discusses forecasting models in GIS-based systems but does not explain the technical details of these models. Readers interested in the mechanics of these systems may find this insufficient.

 

Suggestion: Expand on how the models work, specifying the algorithms or data points used in these systems. For example, "The GIS-based system relies on a combination of rainfall data, vegetation indices, and historical outbreak data, processed using [specific model]." Also, explain how real-time adjustments are made based on incoming data.

 

4. Survey for Locusts and Grasshoppers (Lines 162-206)

Comment: The description of aerial surveys and local community engagement is strong, but the technical aspects of drone usage are underdeveloped. There is also limited discussion on the accuracy of these detection methods.

 

Suggestion: Provide more details about the drone technology used, such as flight altitude, camera resolution, or the integration of AI for detection. Additionally, include data on how accurate these methods are compared to traditional ground-based surveys.

 

5. Chemical Pesticide Use (Lines 238-260)

Comment: This section discusses strip spraying in great detail but lacks comparative data on the environmental impact of different methods, such as blanket vs. strip spraying.

 

Suggestion: Include a comparative analysis of environmental impacts, such as pesticide drift reduction or impact on non-target species. You might also reference studies showing how strip spraying minimizes chemical use, such as "Strip spraying has been shown to reduce pesticide usage by X% while maintaining Y% effectiveness (Author et al., 2022)."

 

6. Biopesticide Use (Lines 283-353)

Comment: The section on biopesticides offers a well-rounded discussion, but it could benefit from more specific examples of field trials, particularly outside of Australia and China. The cost and public perception issues are mentioned, but the latter could be explored more deeply.

 

Suggestion: Include specific success metrics from field trials in additional countries, such as yield improvement, pest mortality rates, or cost reductions. For public perception, you could discuss the cultural challenges in adopting biopesticides, particularly in developing countries, and suggest ways to overcome these barriers through education or government support.

 

7. Conclusion (Lines 358-378)

Comment: The conclusion summarizes the key findings but does not suggest future research directions in enough detail. Given the importance of technological advancements, there could be a stronger emphasis on the future potential of drone usage, AI integration, and climate models in pest management.

 

Suggestion: Add a section proposing future research, such as "Future studies should focus on improving the accuracy of forecasting models by integrating AI and machine learning algorithms to better predict locust movement. Additionally, further exploration into the use of drones for large-scale detection could significantly reduce survey costs and improve response times."

 

8. Figures and Tables

Comment: The current figures, such as the aerial view of locust bands, are useful, but some lack clarity and scale markers, which may hinder interpretation.

 

Suggestion: Enhance the quality of figures by increasing the resolution and ensuring all relevant details (e.g., scale, altitude) are clearly labeled. Additionally, consider adding a table that compares the efficacy and environmental impact of various treatment methods (e.g., blanket spraying, strip spraying, biopesticides).

 

9. References (Lines 385-552)

Comment: The references are comprehensive, but several important recent studies on climate change and locust outbreaks seem to be missing. The inclusion of more geographically diverse sources could enhance the global applicability of the paper.

 

Suggestion: Add more recent references that discuss the role of climate change in locust outbreaks and management strategies, such as studies from regions experiencing significant shifts in pest patterns due to changing climate conditions (e.g., Africa, Middle East).

 

10. Language and Clarity

Comment: The paper is generally well-written, but there are occasional ambiguities, particularly when discussing technical processes like GIS modeling or pesticide application methods.

 

Suggestion: Revise the text for clarity, particularly in sections discussing technical methods. Use more precise language and avoid overly general terms. For example, replace "vegetation condition" with "Normalized Difference Vegetation Index (NDVI)" when referring to satellite data.

 

Author Response

Specific Comments and Suggestions for Revisions

1. Abstract (Lines 8-26)

Comment: The abstract provides a broad overview of the main topics, but it lacks specific quantitative or qualitative results from the discussed methodologies. It should briefly mention the effectiveness of techniques such as biopesticides and strip spraying.

 Reviewer 3:

Suggestion: Add a sentence that summarizes the key findings or results from biopesticide use or forecasting systems, such as "Biopesticides were found to reduce pesticide application by X%, with a Y% reduction in non-target species impacts."

End of abstract, I added: All of these techniques have proven to be very effective in managing locust populations while reducing the risk to the natural environment and human health. The % reduction in chemical use has been added at the end of section 4.2.

2. Introduction (Lines 29-65)

Comment: The introduction effectively sets up the problem, but there is no direct mention of climate change, which is a significant factor in locust and grasshopper outbreaks. Climate variability could be better integrated into the scope of the problem.  

Climate change has barely effected World’s best practice so far; I have added more about human activities including climate change to the conclusions.

Suggestion: Include a brief mention of how climate change exacerbates locust outbreaks, with references to recent research. For example, "Climate change, particularly increasing variability in rainfall, has been linked to more frequent and severe locust outbreaks (Author et al., 2021)."

Already in conclusions: expanded.

3. Preventive Management (Lines 90-108)

Comment: The section on preventive management discusses forecasting models in GIS-based systems but does not explain the technical details of these models. Readers interested in the mechanics of these systems may find this insufficient.

Suggestion: Expand on how the models work, specifying the algorithms or data points used in these systems. For example, "The GIS-based system relies on a combination of rainfall data, vegetation indices, and historical outbreak data, processed using [specific model]." Also, explain how real-time adjustments are made based on incoming data.

Added to second paragraph of Part 2: The accuracy of the models is based on continuing research on the critical factors in population dynamics of the species concerned and on an analysis of the accuracy of previous forecasts with the forecasts being adjusted based on incoming survey and meteorological data.

4. Survey for Locusts and Grasshoppers (Lines 162-206)

Comment: The description of aerial surveys and local community engagement is strong, but the technical aspects of drone usage are underdeveloped. There is also limited discussion on the accuracy of these detection methods.

Accuracy demonstrated by its continued operational use: added to end of third paragraph of section 3 (lines 212-214 of revised manuscript): In Australia, aerial survey is the method of choice in locating dense band infestations and has proven to be a rapid method of efficiently and effectively managing large scale locust infestations.

Suggestion: Provide more details about the drone technology used, such as flight altitude, camera resolution, or the integration of AI for detection. Additionally, include data on how accurate these methods are compared to traditional ground-based surveys.

Drone usage is underdeveloped because as I say in the second last paragraph of section 4.3, initial studies are underway.  Only experimental work has been done so far are drones are not YET part of world’s best practice.  

 

5. Chemical Pesticide Use (Lines 238-260)

Comment: This section discusses strip spraying in great detail but lacks comparative data on the environmental impact of different methods, such as blanket vs. strip spraying.

Suggestion: Include a comparative analysis of environmental impacts, such as pesticide drift reduction or impact on non-target species. You might also reference studies showing how strip spraying minimizes chemical use, such as "Strip spraying has been shown to reduce pesticide usage by X% while maintaining Y% effectiveness (Author et al., 2022)."

Information added to last part of section 4.2 (lines 276-278 of the revised document).

 

6. Biopesticide Use (Lines 283-353)

Comment: The section on biopesticides offers a well-rounded discussion, but it could benefit from more specific examples of field trials, particularly outside of Australia and China. The cost and public perception issues are mentioned, but the latter could be explored more deeply.

Suggestion: Include specific success metrics from field trials in additional countries, such as yield improvement, pest mortality rates, or cost reductions. For public perception, you could discuss the cultural challenges in adopting biopesticides, particularly in developing countries, and suggest ways to overcome these barriers through education or government support.

 A summary of field trial results already presented in the second paragraph of 4.4 but more information on mortality rates from field trials added in the first paragraph of section 4.4:            Mortalities of more than 90% are common with both Metarhizium biopesticides [57, 61, 65], and with Nosema [66-68], but these high levels of mortality against the target pest are achieved while preserving natural enemies [61, 69],

Added to the last paragraph of the section on biopesticides: Expansion of the use of biopesticides in other countries with locust/grasshopper outbreaks will require not only a program of both research that demonstrates effectiveness but also an education program as to the benefits of biopesticides to overcome both political and perceived operational impediments to the widespread implementation of biopesticides as an essential part of local management programs.

7. Conclusion (Lines 358-378)

Comment: The conclusion summarizes the key findings but does not suggest future research directions in enough detail. Given the importance of technological advancements, there could be a stronger emphasis on the future potential of drone usage, AI integration, and climate models in pest management.

 

Suggestion: Add a section proposing future research, such as "Future studies should focus on improving the accuracy of forecasting models by integrating AI and machine learning algorithms to better predict locust movement. Additionally, further exploration into the use of drones for large-scale detection could significantly reduce survey costs and improve response times."

The conclusions have been expanded significantly as per reviewer’s suggestions, including an emphasis on research needed in many areas if preventive management is to continue and expand in the face of restrictions on chemical pesticide use and climate change.

8. Figures and Tables

Comment: The current figures, such as the aerial view of locust bands, are useful, but some lack clarity and scale markers, which may hinder interpretation.

Suggestion: Enhance the quality of figures by increasing the resolution and ensuring all relevant details (e.g., scale, altitude) are clearly labeled. Additionally, consider adding a table that compares the efficacy and environmental impact of various treatment methods (e.g., blanket spraying, strip spraying, biopesticides).

More explanation given for figure of bands seen from the air.

 Table 1 has been added on biopesticides currently used as suggested by reviewer #1. Efficacy and environmental impact covered by comments for section 5 in lines 278-280 of revised document.

 

9. References (Lines 385-552)

Comment: The references are comprehensive, but several important recent studies on climate change and locust outbreaks seem to be missing. The inclusion of more geographically diverse sources could enhance the global applicability of the paper.

 

Suggestion: Add more recent references that discuss the role of climate change in locust outbreaks and management strategies, such as studies from regions experiencing significant shifts in pest patterns due to changing climate conditions (e.g., Africa, Middle East).

 Two examples of the effects of human activities and climate change are given in the first paragraph of the conclusions, and the author nearly completed a paper on how human activities and climate change have led to the recent upsurge in the South American locust in a follow-up to the work done in reference 75.

An overall comment: many locust and grasshopper management programs include most of the latest techniques as part of World’s Best Practice, and these programs have been emphasized in this paper.  But for various political and other reasons, other management programs have not implemented Best Practice, and the author has been careful not to name them, but has emphasized in the last sentence of the biopesticides section (lines 392-397 of revised document) the need for expansion of the use of biopesticides and at the end of the conclusions (lines 427-430), re adaptation of all techniques to local conditions.

10. Language and Clarity

Comment: The paper is generally well-written, but there are occasional ambiguities, particularly when discussing technical processes like GIS modeling or pesticide application methods.

 

Suggestion: Revise the text for clarity, particularly in sections discussing technical methods. Use more precise language and avoid overly general terms. For example, replace "vegetation condition" with "Normalized Difference Vegetation Index (NDVI)" when referring to satellite data.

NDVI already mentioned: The FAO website is a good example of the many types of information used to determine where rainfall has occurred: interpolated estimates of rainfall distribution, Normalized Difference Vegetation Index (NDVI) of vegetation condition, and soil moisture estimates.

Author Response File: Author Response.docx