Climate change and diseases of food crops

Despite complex regional patterns of projected climate change, significant decreases in food crop yields have been predicted using the 'worst case' CO2 emission scenario (A1FI) of the Intergovernmental Panel on Climate Change. Overall, climate change is predicted to have a progressively negative effect on the yield of food crops, particularly in the absence of efforts to mitigate global CO2 emissions. As with all species, plant pathogens will have varying responses to climate change. Whilst the life cycle of some pathogens will be limited by increasing temperatures, e.g. Puccinia striiformis f.sp. tritici, other climatic factors such as increasing atmospheric CO2, may provide more favourable conditions for pathogens such as Fusarium pseudograminearum. Based on published literature and unpublished work in progress, we have reviewed the qualitative effects of climate change on pathogens that cause disease of four major food crops: wheat, rice, soybean and potato. The limited data show that the influence will be positive, negative or neutral, depending on the host-pathogen interaction. Quantitative analysis of climate change on pathogens of these crops is largely lacking, either from field or laboratory studies or from modelling-based assessments. Systematic quantitative analysis of these effects will be necessary in developing future disease management plans, such as plant breeding, altered planting schedules, chemical and biological control methods and increased monitoring for new disease threats.