A White Paper on Global Wheat Health Based on Scenario Development and Analysis

Abstract

Scenario analysis constitutes a useful approach to synthesize knowledge and derive hypotheses in the case of complex systems that are documented with mainly qualitative or very diverse information. In this article, a framework for scenario analysis is designed and then, applied to global wheat health within a timeframe from today to 2050. Scenario analysis entails the choice of settings, the definition of scenarios of change, and the analysis of outcomes of these scenarios in the chosen settings. Three idealized agrosystems, representing a large fraction of the global diversity of wheat-based agrosystems, are considered, which represent the settings of the analysis. Several components of global changes are considered in their consequences on global wheat health: climate change and climate variability, nitrogen fertilizer use, tillage, crop rotation, pesticide use, and the deployment of host plant resistances. Each idealized agrosystem is associated with a scenario of change that considers first, a production situation and its dynamics, and second, the impacts of the evolving production situation on the evolution of crop health. Crop health is represented by six functional groups of wheat pathogens: the pathogens associated with Fusarium head blight; biotrophic fungi, Septoria-like fungi, necrotrophic fungi, soilborne pathogens, and insect-transmitted viruses. The analysis of scenario outcomes is conducted along a risk-analytical pattern, which involves risk probabilities represented by categorized probability levels of disease epidemics, and risk magnitudes represented by categorized levels of crop losses resulting from these levels of epidemics within each production situation. The results from this scenario analysis suggest an overall increase of risk probabilities and magnitudes in the three idealized agrosystems. Changes in risk probability or magnitude however vary with the agrosystem and the functional groups of pathogens. We discuss the effects of global changes on the six functional groups, in terms of their epidemiology and of the crop losses they cause. Scenario analysis enables qualitative analysis of complex systems, such as plant pathosystems that are evolving in response to global changes, including climate change and technology shifts. It also provides a useful framework for quantitative simulation modeling analysis for plant disease epidemiology.

Agriculture Development, Pesticide Application and Its Impact on the Environment

“…Temperature, humidity, precipitation, radiation, and dew are the main climatic factors that impact crop diseases [92,94]. Climate conditions not only directly change the biological condition of plant hosts, pathogens, and vectors, and therefore influence crop diseases, they also directly impact the severity of diseases and plant losses [113][114][115][116][117][118][119][120][121][122].…”

EPIC‐GILSYM: Modelling crop‐pest insect interactions and management with a novel coupled crop‐insect model

“…In EPIC‐GILSYM, changing environmental conditions serve as a driver of change for all other processes, and cropping systems can be well defined in terms of input intensity, which is an important aspect in the mechanistic simulation of food systems (Savary, Bregaglio, et al, ). The model can also be used to support analyses like the one by Savary, Djurle, et al (), where the authors analysed the potential future development of global wheat health. Their risk analysis considered the effects of changes in climate, fertilizer inputs, tillage and crop rotation and was based on expert opinions on their impact on three representative wheat cropping systems.…”

An outlook on wheat health in Europe from a network of field experiments

“…The main wheat diseases occurring in Europe are caused by fungal pathogens (Jørgensen et al, 2014;Figueroa et al, 2018;Singh et al, 2016;Savary et al, 2017;2019). Septoria tritici blotch, caused by Zymoseptoria tritici, is an important disease in most parts of EU (Fones and Gurr, 2015;Savary et al, 2015;2019).…”

“…Because wheat health problems vary over time (from season to season) and space, such an assessment needs to be conducted every year, in a range of geographical locations. Such assessments are not available currently for wheat in EU: only fragmented information of wheat health status is available, at the scale of Europe (e.g., Jørgensen et al, 2014;Figueroa et al, 2018;Singh et al, 2016;Savary et al, 2017;2019), or at the country scale (e.g., Jahn et al, 2012;Savary et al, 2016a;Djurle et al, 2018;Willocquet et al, 2018). In the same way, information on fungicide use is also incomplete, and the information pertaining, e.g., to the number of fungicide applications on wheat crops in Europe, is seldom available.…”