Influence of climate change on plant disease infections and epidemics caused by viruses and bacteria.

Abstract This review is motivated by (i) the magnitude of the threat to world food security and diversity of natural vegetation posed by viral and bacterial pathogens of plants at a time of accelerating climate change; and (ii) the inadequate attention given to this subject by earlier reviews on climate change and plant disease. It starts by providing background information on current climate change predictions, the increasing worldwide importance of viral and bacterial diseases, critical features of their pathosystems and the general influence of environmental factors upon them. It then develops comprehensive climatic and biological frameworks and uses them to determine the likely influences of direct and indirect climate change parameters on the many different host, vector and pathogen parameters that represent the diversity of viral and bacterial pathosystems. This approach proved a powerful way to identify the relevant international research data available and many information gaps where research is needed in the future. The analysis suggested that climate change is likely to modify many critical viral and bacterial epidemic components in different ways, often resulting in epidemic enhancement but sometimes having the opposite effect, depending on the type of pathosystem and circumstances. With vector-borne pathosystems and new encounter scenarios, the complication of having to consider the effects climate change parameters on diverse types of vectors and the emergence of previously unknown pathogens added important additional variables. The increasing difficulties in controlling damaging plant viral and bacterial epidemics predicted to arise from future climate instability warrants considerable research effort to safeguard world food security and biodiversity.