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Journal ArticleDOI

Integrating pests and pathogens into the climate change/food security debate

01 Jul 2009-Journal of Experimental Botany (Oxford University Press)-Vol. 60, Iss: 10, pp 2827-2838
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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Citations
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Journal ArticleDOI
12 Apr 2012-Nature
TL;DR: It is argued that nascent fungal infections will cause increasing attrition of biodiversity, with wider implications for human and ecosystem health, unless steps are taken to tighten biosecurity worldwide.
Abstract: The past two decades have seen an increasing number of virulent infectious diseases in natural populations and managed landscapes. In both animals and plants, an unprecedented number of fungal and fungal-like diseases have recently caused some of the most severe die-offs and extinctions ever witnessed in wild species, and are jeopardizing food security. Human activity is intensifying fungal disease dispersal by modifying natural environments and thus creating new opportunities for evolution. We argue that nascent fungal infections will cause increasing attrition of biodiversity, with wider implications for human and ecosystem health, unless steps are taken to tighten biosecurity worldwide.

2,408 citations

Journal ArticleDOI
TL;DR: In this paper, a comprehensive summary of studies that simulate climate change impacts on agriculture are reported in a meta-analysis, which suggests that aggregate yield losses should be expected for wheat, rice and maize in temperate and tropical growing regions even under relatively moderate levels of local warming.
Abstract: A comprehensive summary of studies that simulate climate change impacts on agriculture are now reported in a meta-analysis. Findings suggest that, without measures to adapt to changing conditions, aggregate yield losses should be expected for wheat, rice and maize in temperate and tropical growing regions even under relatively moderate levels of local warming.

1,458 citations

Journal ArticleDOI
TL;DR: This work proposes a framework based on ideas from global-change biology, community ecology, and invasion biology that uses community modules to assess how species interactions shape responses to climate change.
Abstract: Predicting the impacts of climate change on species is one of the biggest challenges that ecologists face Predictions routinely focus on the direct effects of climate change on individual species, yet interactions between species can strongly influence how climate change affects organisms at every scale by altering their individual fitness, geographic ranges and the structure and dynamics of their community Failure to incorporate these interactions limits the ability to predict responses of species to climate change We propose a framework based on ideas from global-change biology, community ecology, and invasion biology that uses community modules to assess how species interactions shape responses to climate change

1,169 citations

01 Jan 2014
TL;DR: The questions for this chapter are how far climate and its change affect current food production systems and food security and the extent to which they will do so in the future.
Abstract: Many definitions of food security exist, and these have been the subject of much debate. As early as 1992, Maxwell and Smith (1992) reviewed more than 180 items discussing concepts and definitions, and more definitions have been formulated since (DEFRA, 2006). Whereas many earlier definitions centered on food production, more recent definitions highlight access to food, in keeping with the 1996 World Food Summit definition (FAO, 1996) that food security is met when “all people, at all times, have physical and economic access to sufficient, safe, and nutritious food to meet their dietary needs and food preferences for an active and healthy life.” Worldwide attention on food access was given impetus by the food “price spike” in 2007–2008, triggered by a complex set of long- and short-term factors (FAO, 2009b; von Braun and Torero, 2009). FAO concluded, “provisional estimates show that, in 2007, 75 million more people were added to the total number of undernourished relative to 2003–05” (FAO, 2008); this is arguably a low-end estimate (Headey and Fan, 2010). More than enough food is currently produced per capita to feed the global population, yet about 870 million people remained hungry in the period from 2010 to 2012 (FAO et al., 2012). The questions for this chapter are how far climate and its change affect current food production systems and food security and the extent to which they will do so in the future (Figure 7-1).

960 citations


Cites background from "Integrating pests and pathogens int..."

  • ...The potential influence of pests and diseases is commonly beyond the scope of such studies (Gregory et al., 2009)....

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Journal ArticleDOI
TL;DR: This paper reviews recent literature concerning a wide range of processes through which climate change could potentially impact global-scale agricultural productivity, and presents projections of changes in relevant meteorological, hydrological and plant physiological quantities from a climate model ensemble to illustrate key areas of uncertainty.
Abstract: This paper reviews recent literature concerning a wide range of processes through which climate change could potentially impact global-scale agricultural productivity, and presents projections of changes in relevant meteorological, hydrological and plant physiological quantities from a climate model ensemble to illustrate key areas of uncertainty. Few global-scale assessments have been carried out, and these are limited in their ability to capture the uncertainty in climate projections, and omit potentially important aspects such as extreme events and changes in pests and diseases. There is a lack of clarity on how climate change impacts on drought are best quantified from an agricultural perspective, with different metrics giving very different impressions of future risk. The dependence of some regional agriculture on remote rainfall, snowmelt and glaciers adds to the complexity. Indirect impacts via sea-level rise, storms and diseases have not been quantified. Perhaps most seriously, there is high uncertainty in the extent to which the direct effects of CO2 rise on plant physiology will interact with climate change in affecting productivity. At present, the aggregate impacts of climate change on global-scale agricultural productivity cannot be reliably quantified.

828 citations


Cites background from "Integrating pests and pathogens int..."

  • ...This may be through impacts of warming or drought on the resistance of crops to specific diseases and through the increased pathogenicity of organisms by mutation induced by environmental stress (Gregory et al. 2009)....

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References
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Journal ArticleDOI
TL;DR: In this article, the authors combine projections from the UK Hadley Centre's HadRM03 climate change model for Southern Britain with a general mechanistic model of the interaction between climate, temperate grass physiology and cereal aphid population dynamics.
Abstract: Climate change will drive dramatic changes in the abundance and distribution of species. Assessing the impacts of climate change on our agricultural systems is essential for mitigation planning. Here, I combine projections from the UK Hadley Centre’s HadRM03 climate change model for Southern Britain with a general mechanistic model of the interaction between climate, temperate grass physiology and cereal aphid population dynamics. Aphids are one of the largest and most important groups of crop pests and disease vectors worldwide but particularly in temperate regions. The model predicts an increasingly dramatic decline in cereal aphid abundance from the 1961 to 1990 baseline with increasing CO2 emissions: low emissions 5� 5%, medium low 5� 12%, medium high 5� 61%, and high 5� 92%. Of the six climate variables used in the model, changes in temperature and rainfall were the most important across all emissions scenarios and, counter-intuitively, the direct impact of elevated CO2 actually declines as emissions increase. The results suggest that the pest status of cereal aphids in Southern Britain will significantly decline by the end of this century.

77 citations


"Integrating pests and pathogens int..." refers background in this paper

  • ...Similarly, while a combination of heat and drought may reduce the population of cereal aphids in southern Britain, if aphid predators are affected to an even greater degree, then the predicted reduction in aphids may be negated (Newman, 2005)....

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  • ...Range and severity of a plant disease increased by global warming....

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Journal ArticleDOI
TL;DR: Investigation of the impact of 10 years of experimental summer drought and increased summer rainfall manipulations on the soil fauna of a calcareous grassland finds that the responses of root herbivores to an increased incidence of summer droughts are likely to vary, depending on their feeding strategy and life history.

74 citations


"Integrating pests and pathogens int..." refers background in this paper

  • ...For example, Staley et al. (2007) investigated the impacts of enhanced summer rainfall and drought conditions on soildwelling Agriotes lineatus (wireworms) in grassland plots....

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  • ...Staley et al. (2007) found that there was a rapid increase in the population of wireworms in the upper soil as a consequence of enhanced summer rainfall events compared to ambient and drought conditions (Fig....

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01 Jan 2002

70 citations


Additional excerpts

  • ...Overall, the results of this and subsequent work demonstrated that climate change would benefit the cereal production of developed countries more than the developing countries, even if cropping practices evolved to allow more than one rainfed crop per year (Fischer et al., 2002, 2005)....

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Journal ArticleDOI
TL;DR: The need to consider both canopy size and host resistance in assessing the influence of elevated CO(2) on plant disease is highlighted, as Fitzroy developed a dense and enlarged canopy.
Abstract: Pangga, I. B., Chakraborty, S., and Yates, D. 2004. Canopy size and induced resistance in Stylosanthes scabra determine anthracnose severity at high CO2. Phytopathology 94:221-227. This study examines the relative importance of canopy size and induced resistance to Colletotrichum gloeosporioides at 350- and 700-ppm atmospheric CO2 concentrations on susceptible Stylosanthes scabra ‘Fitzroy’ from two studies in a controlled environment facility (CEF) and in the field. Plants were grown at the two CO2 concentrations in a repeated experiment in the CEF and inoculated at 6, 9, or 12 weeks of age. Although the physiological maturity of plants was at a similar stage for all three ages, the number of lesions per plant increased with increasing plant age at both CO2 concentrations. At 350 ppm, the increase was associated with canopy size and increasing infection efficiency of the pathogen, but at 700 ppm, it was associated only with canopy size, because infection efficiency did not change with increasing age. A level of resistance was induced in plants at 700 ppm CO2. In a second study, plants were raised for 12 to 14 weeks at the two CO2 concentrations in the CEF and exposed to C. gloeosporioides inoculum in replicated field plots under ambient CO2 over three successive years. Fitzroy developed a dense and enlarged canopy, with 28 to 46% more nodes, leaf area, and aboveground biomass at high CO2 than at low CO2. Up to twice as many lesions per plant were produced in the high CO2 plants, because the enlarged canopy trapped many more pathogen spores. The transient induced resistance in high CO2 plants failed to operate when exposed to pathogen inoculum under ambient CO2 in the field. These results highlight the need to consider both canopy size and host resistance in assessing the influence of elevated CO2 on plant disease.

67 citations


"Integrating pests and pathogens int..." refers background in this paper

  • ...While elevated CO2 has direct effects on plant growth, it can also result in indirect effects such as reduced expression of induced resistance (Pangga et al., 2004)....

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  • ...While elevated CO2 has direct effects on plant growth, it can also result in indirect effects such as reduced expression of induced resistance (Pangga et al., 2004)....

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Journal ArticleDOI
TL;DR: Four stem rust resistance genes (Sr13, Sr30, Sr36 and SrTmp) were found to confer resistance to most of the races prevalent in Ethiopia and could be used in breeding for resistance to stem rust in Ethiopia.
Abstract: Wheat stem rust samples were collected in 2006 and 2007 in the Arsi, Bale, Shewa and northwest regions of Ethiopia to determine virulence diversity and race distribution in Puccinia graminis f.sp. tritici populations. Stem rust incidence was high in Arsi, Bale and east Shewa. In northwest Ethiopia, and north and west Shewa, stem rust was prevalent at low levels. A total of 152 isolates was analysed and 22 races were identified. Races TTKSR (Ug99), TTHSR and RRTTR were predominant, with frequencies of 26·6, 17·7 and 11·1%, respectively. These races were also detected in all regions. The highly virulent race designated Ug99 was present throughout the country and dominated in all regions except northwest Ethiopia. A variant of Ug99 virulent against the stem rust resistance gene Sr24 was not detected in this study. Four stem rust resistance genes (Sr13, Sr30, Sr36 and SrTmp) were found to confer resistance to most of the races prevalent in Ethiopia. With the exception of Sr30, which is not effective against Ug99, these genes could be used in breeding for resistance to stem rust in Ethiopia.

66 citations


"Integrating pests and pathogens int..." refers background in this paper

  • ...Changing climate has already affected the geographical distribution of some crop pests and pathogens [e.g. Puccinia graminis f.sp. tritici (stem rust) and Dickea dianthicola; Woods et al., 2005; Admassu et al., 2009; courtesy of DELl Cooke, SCRI....

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  • ...Another example of this type of model is the increased range of stem rust, and, in particular, the race known as Ug99 which has virulence towards the Sr31 resistance gene (1B/1R translocation) which is used extensively in wheat varieties across the world (Admassu et al., 2009)....

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