Integrating pests and pathogens into the climate change/food security debate
TL;DR: More mechanistic inclusion of pests and pathogen effects in crop models would lead to more realistic predictions of crop production on a regional scale and thereby assist in the development of more robust regional food security policies.
Abstract: While many studies have demonstrated the sensitivities of plants and of crop yield to a changing climate, a major challenge for the agricultural research community is to relate these findings to the broader societal concern with food security. This paper reviews the direct effects of climate on both crop growth and yield and on plant pests and pathogens and the interactions that may occur between crops, pests, and pathogens under changed climate. Finally, we consider the contribution that better understanding of the roles of pests and pathogens in crop production systems might make to enhanced food security. Evidence for the measured climate change on crops and their associated pests and pathogens is starting to be documented. Globally atmospheric [CO(2)] has increased, and in northern latitudes mean temperature at many locations has increased by about 1.0-1.4 degrees C with accompanying changes in pest and pathogen incidence and to farming practices. Many pests and pathogens exhibit considerable capacity for generating, recombining, and selecting fit combinations of variants in key pathogenicity, fitness, and aggressiveness traits that there is little doubt that any new opportunities resulting from climate change will be exploited by them. However, the interactions between crops and pests and pathogens are complex and poorly understood in the context of climate change. More mechanistic inclusion of pests and pathogen effects in crop models would lead to more realistic predictions of crop production on a regional scale and thereby assist in the development of more robust regional food security policies.
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TL;DR: Dung beetles enhanced plant growth and nitrogen content in plants experiencing drought, and their effects did not change plant suitability to an above-ground herbivore, pointing to potential beneficial role for insect ecosystem engineers in climate change adaptation and crop protection.
Abstract: Summary
Climate change models predict more extreme rainfall patterns, ranging from droughts to deluges, which will inevitably affect primary productivity in many terrestrial ecosystems. Insects within the ecosystem, living above- and below-ground, may modify plant responses to water stress. For example, some functional groups improve soil conditions via resource provision, potentially alleviating water stress. Enhanced resource provision may, however, render plants more susceptible to herbivores and negate beneficial effects.
Using a model system, we tested how plants (Brassica oleracea) responded to drought, ambient and increased precipitation scenarios when interacting with both a soil conditioning ecosystem engineer (dung beetles; Bubas bison) and an above-ground herbivore, the major crop pest diamondback moth (Plutella xylostella).
Dung beetles enhanced soil water retention by 10% and promoted growth in plants subjected to drought by 280%, relieving the impacts of water stress on plants. Under drought conditions, plants grown with dung beetles had c. 30% more leaves and were over twice as tall as those without dung beetles. Dung beetles produced a 2·7-fold increase in nitrogen content and more than a threefold increase in carbon content of the shoots, though shoot concentrations of nitrogen and carbon were unchanged. Carbon concentrations in roots, however, were increased by dung beetles under both ambient and increased precipitation regimes.
Increased precipitation reduced root and shoot nitrogen concentrations by 16% and 30%, relative to plants under ambient regimes, respectively, most likely due to dilution effects of increased plant growth under increased precipitation. Soil carbon and nitrogen concentrations were largely unaffected.
While dung beetles enhanced plant growth and nitrogen content in plants experiencing drought, the anticipated increase in plant suitability to herbivores did not arise, possibly because shoot nitrogen concentrations and C:N ratio were unaffected.
To our knowledge, this is the first report of an insect ecosystem engineer alleviating the effects of predicted drought events on plants via physical manipulation of the soil matrix. Moreover, their effects did not change plant suitability to an above-ground herbivore, pointing to potential beneficial role for insect ecosystem engineers in climate change adaptation and crop protection.
41 citations
Cites background from "Integrating pests and pathogens int..."
...Integration of pests and pathogens into food security– climate change research has been advocated convincingly (Gregory et al. 2009; Newton, Johnson & Gregory 2011), but the role of ecological service providers like dung beetles has received far less attention....
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...Integration of pests and pathogens into food security– climate change research has been advocated convincingly (Gregory et al. 2009; Newton, Johnson & Gregory 2011),...
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TL;DR: How the nutrient content of insect-infested stored grain depends upon the grain type, the infesting insect, and the infestation level is indicated, which has consequences for human nutrition beyond those of grain weight loss.
Abstract: Our understanding and prevention of postharvest losses are critical if we are to feed a growing global population. Insect infestation-related losses of stored commodities are typically considered only in terms of quantitative, physical weight loss. Insect infestation affects the nutritional value and some nutritional components are impacted more severely than others. We infested maize and cowpea grain with commonly occurring stored product insect pests, and mapped infestation levels against nutritional composition over a 4-to-6 month storage period to analyse how insect infestation relates to different macro- and micro-nutrient contents. Insect infestation decreased the carbohydrate content of the stored grains, causing a relative increase in the proportion of protein and fibre in the remaining grain, and moisture content also increased. Sitophilus zeamais preferentially fed in the floury endosperm of maize, resulting in more carbohydrate loss relative to protein loss. Conversely, Prostephanus truncatus consumed the germ and endosperm, disproportionately reducing the fat, protein, iron and zinc grain contents. Nutrients are distributed more homogenously within cowpea than in maize grains, but Callosobruchus maculatus infestation increased the relative protein, fat, iron and zinc to carbohydrate ratios. This indicates how the nutrient content of insect-infested stored grain depends upon the grain type, the infesting insect, and the infestation level. Insect infestation therefore has consequences for human nutrition beyond those of grain weight loss. Using data collected on the changing nutritional composition of grain over time, with and without insect infestation, we modelled the associations between infestation and nutritional quality to predict estimated nutritional losses that could be associated with consumption of insect-infested stored maize and cowpea.
40 citations
Cites background from "Integrating pests and pathogens int..."
...…1 Natural Resources Institute (NRI), University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK occur both pre- and post-harvest, is imperative (Oerke 2006; Gregory et al. 2009; World Bank et al. 2011; Gustavsson et al. 2011; Savary et al. 2012; Savary et al. 2017; Stathers and Mvumi in press)....
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TL;DR: Highly resistant accessions originating from a regional collection were found among the five sorghum races (kafir, guinea, caudatum, bicolor and durra), and are now implemented in new sorghums disease resistance programs.
Abstract: In order to understand the underlaying causes of new severe turcicum leaf blight outbreaks in East Africa, a survey was undertaken in Uganda to examine the sorghum—Setosphaeria turcica interaction in terms of disease severity and incidence, the overall fungal population structure, and new resistant resources. Highest disease severities were recorded on caudatum accessions, whereas kafir genotypes were most resistant. The disease was more severe in the most humid farmlands compared to moderately dry agro-ecologies. In districts with wide adoption of the Epuripur variety a very high incidence (100%) of turcicum leaf blight was found. The two S. turcica mating type genes MAT1-1 and MAT1-2 assessed on fungal isolates deriving from both sorghum and maize diseased leaves were found in 20 of 23 districts sampled and in equal proportions. Upon cross inoculation on maize differential lines, four S. turcica isolates were identified as race 1, two as race 2, and one isolate corresponded to race 0 and race 3, respectively. The remaining 10 S. turcica isolates did not cause any disease symptoms on the maize lines assessed. Highly resistant accessions originating from a regional collection were found among the five sorghum races (kafir, guinea, caudatum, bicolor and durra), and are now implemented in new sorghum disease resistance programs.
40 citations
Cites background from "Integrating pests and pathogens int..."
...tance response as seen in other pathosystems (Gregory et al. 2009), or disease susceptibility conferred by resistance genes (Lorang et al....
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...…to explain and may involve one or more factors such as a different recognition system, temperature sensitivity that erodes the resis- tance response as seen in other pathosystems (Gregory et al. 2009), or disease susceptibility conferred by resistance genes (Lorang et al. 2007; Faris et al. 2010)....
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TL;DR: In this paper, weather data generated for different parts of the UK under five climate change scenarios were inputted into weather-based models for predicting oilseed rape yields and yield losses from the two most important diseases, phoma stem canker and light leaf spot.
Abstract: Weather data generated for different parts of the UK under five climate change scenarios (baseline, 2020s low CO2 emissions, 2020s high emissions, 2050s low emissions, 2050s high emissions) were inputted into weather-based models for predicting oilseed rape yields and yield losses from the two most important diseases, phoma stem canker and light leaf spot. An economic analysis of the predictions made by the models was done to provide a basis to guide government and industry planning for adaptation to effects of climate change on crops to ensure future food security. Modelling predicted that yields of fungicide-treated oilseed rape would increase by the 2020s and continue to increase by the 2050s, particularly in Scotland and northern England. If stem canker and light leaf spot were effectively controlled, the value of the crop was predicted to increase above the baseline 1980s value by £13 M in England and £28 M in Scotland by the 2050s under a high CO2 emissions scenario. However, in contrast to predictions that phoma stem canker will increase in severity and range with climate change, modelling indicated that losses due to light leaf spot will decrease in both Scotland and England. Combined losses from both phoma stem canker and light leaf spot are predicted to increase, with yield losses of up to 40% in southern England and some regions of Scotland by the 2050s under the high emission scenarios. For this scenario, UK disease losses are predicted to increase by £50 M (by comparison with the baseline losses). However, the predicted increases in fungicide-treated (potential) yield and phoma stem canker/light leaf spot yield losses compensate for each other so that the net UK losses from climate change for untreated oilseed rape are small.
39 citations
Cites background from "Integrating pests and pathogens int..."
...This work illustrates how, worldwide, increased disease losses may be associated with increases in severity of existing diseases or spread of diseases to new areas to threaten crop production (Anderson et al. 2004; Chakraborty et al. 2000; Garrett et al. 2006; Gregory et al. 2009)....
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...2003) of crop production systems in different areas of the world (Gregory et al. 2009)....
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...The food security problems associated with crop diseases are now becoming more acute due to climate change (Anderson et al. 2004; Chakraborty et al. 2000; Garrett et al. 2006; Gregory et al. 2009; Stern 2007), especially for farmers in marginal areas such as subSaharan Africa (Schmidhuber and Tubiello 2007)....
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...…problems associated with crop diseases are now becoming more acute due to climate change (Anderson et al. 2004; Chakraborty et al. 2000; Garrett et al. 2006; Gregory et al. 2009; Stern 2007), especially for farmers in marginal areas such as subSaharan Africa (Schmidhuber and Tubiello 2007)....
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TL;DR: It is shown that enhancing the complexity of a rice production system by adding combinations of compost, azolla, ducks, and fish resulted in strongly increased grain yields and revenues in a season with extremely adverse weather conditions on East Java, Indonesia.
Abstract: Attempts to increase food crop yields by intensifying agricultural systems using high inputs of nonrenewable resources and chemicals frequently lead to de-gradation of natural resources, whereas most technological innovations are not accessible for smallholders that represent the majority of farmers world wide Alternatively, cocultures consisting of assemblages of plant and animal species can support ecological processes of nutrient cycling and pest control, which may lead to increasing yields and declining susceptibility to extreme weather conditions with increasing complexity of the systems Here we show that enhancing the complexity of a rice production system by adding combinations of compost, azolla, ducks, and fish resulted in strongly increased grain yields and revenues in a season with extremely adverse weather conditions on East Java, Indonesia We found that azolla, duck, and fish increased plant nutrient content, tillering and leaf area expansion, and strongly reduced the density of six different pests In the most complex system comprising all components the highest grain yield was obtained The net revenues of this system from sales of rice grain, fish, and ducks, after correction for extra costs, were 114% higher than rice cultivation with only compost as fertilizer These results provide more insight in the agro-ecological processes and demonstrate how complex agricultural systems can contribute to food security in a changing climate If smallholders can be trained to manage these systems and are supported for initial investments by credits, their livelihoods can be improved while producing in an ecologically benign way
38 citations
Cites background from "Integrating pests and pathogens int..."
...…will be variable due to the strong dependence on ecological processes that are susceptible for environmental fluctuations (Morton 2007; Gregory et al. 2009), the improved nutrient status and biological weed and pest control enhance the robustness of the systems (Altieri 1999; Shennan…...
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...Although the revenues from the complex agro-ecosystems will be variable due to the strong dependence on ecological processes that are susceptible for environmental fluctuations (Morton 2007; Gregory et al. 2009), the improved nutrient status and biological weed and pest control enhance the robustness of the systems (Altieri 1999; Shennan 2008), as demonstrated in the extremely unfavorable conditions as experienced in the trial presented here....
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References
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01 Jan 2007
TL;DR: The first volume of the IPCC's Fourth Assessment Report as mentioned in this paper was published in 2007 and covers several topics including the extensive range of observations now available for the atmosphere and surface, changes in sea level, assesses the paleoclimatic perspective, climate change causes both natural and anthropogenic, and climate models for projections of global climate.
Abstract: This report is the first volume of the IPCC's Fourth Assessment Report. It covers several topics including the extensive range of observations now available for the atmosphere and surface, changes in sea level, assesses the paleoclimatic perspective, climate change causes both natural and anthropogenic, and climate models for projections of global climate.
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01 Jul 2001
TL;DR: In this paper, the authors set the stage for impact, adaptation, and vulnerability assessment of climate change in the context of sustainable development and equity, and developed and applied scenarios in Climate Change Impact, Adaptation, and Vulnerability Assessment.
Abstract: Summary for policymakers Technical summary Part I. Setting the Stage for Impact, Adaptation, and Vulnerability Assessment: 1. Overview 2. Methods and tools 3. Development and application of scenarios in Climate Change Impact, Adaptation, and Vulnerability Assessment Part II. Sectors and Systems: Impacts, Adaptation, and Vulnerability: 4. Hydrology and water resources 5. Natural and managed ecosystems 6. Coastal zones and marine ecosystems 7. Energy, industry, and settlements 8. Financial services 9. Human health Part III. Regional Analyses: Impacts, Adaptation, and Vulnerability: 10. Africa 11. Asia 12. Australasia 13. Europe 14. Latin America 15. North America 16. Polar regions (Arctic and Antarctic) 17. Small island states Part IV. Global Issues and Synthesis: 18. Adaptation to climate change in the context of sustainable development and equity 19. Synthesis and integration of impacts, adaptation, and vulnerability Index.
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01 Jan 2007
TL;DR: In this paper, the authors present a cross-chapter case study on climate change and sustainability in natural and managed systems and assess key vulnerabilities and the risk from climate change, and assess adaptation practices, options, constraints and capacity.
Abstract: Foreword Preface Introduction Summary for policymakers Technical summary 1. Assessment of observed changes and responses in natural and managed systems 2. New assessment methodologies and the characterisation of future conditions 3. Fresh water resources and their management 4. Ecosystems, their properties, goods and services 5. Food, fibre and forest products 6. Coastal systems and low-lying areas 7. Industry, settlement and society 8. Human health 9. Africa 10. Asia 11. Australia and New Zealand 12. Europe 13. Latin America 14. North America 15. Polar regions (Arctic and Antarctic) 16. Small islands 17. Assessment of adaptation practices, options, constraints and capacity 18. Inter-relationships between adaptation and mitigation 19. Assessing key vulnerabilities and the risk from climate change 20. Perspectives on climate change and sustainability - 811 Cross-chapter case studies Appendix I. Glossary Appendix II. Contributors to the IPCC WGII Fourth Assessment Report Appendix III. Reviewers of the IPCC WGII Fourth Assessment Report Appendix IV. Acronyms and abbreviations Appendix V. Index and database of regional content Index CD-ROM.
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Journal Article•
TL;DR: In this article, the authors present a document, redatto, voted and pubblicato by the Ipcc -Comitato intergovernativo sui cambiamenti climatici - illustra la sintesi delle ricerche svolte su questo tema rilevante.
Abstract: Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.
4,187 citations