Potential impact of climate change on plant diseases of economic significance to Australia

Burning of fossil fuel, large scale clearing of forests and other human activities have changed global climate. Atmospheric concentration of radiatively active CO2, methane, nitrous oxide and chlorofluorocarbons has increased to cause global warming. In Australia temperature is projected to rise between 1 and 3°C by 2100. This review is the result of a recent workshop on the potential impact of climate change on plant diseases of economic significance to Australia. It gives an overview of projected changes in Australian climate and the current state of knowledge on the effect of climate change on plant diseases. Based on an assessment of important diseases of wheat and other cereals, sugarcane, deciduous fruits, grapevine, vegetables and forestry species, climate change in Australia may reduce, increase or have no effect on some diseases. Impacts will be felt in altered geographical distribution and crop loss due to changes in the physiology of host-pathogen interaction. Changes will occur in the type, amount and relative importance of pathogens and diseases. Host resistance may be overcome more rapidly due to accelerated pathogen evolution from increased fecundity at high CO2, and/or enhanced UV-B radiation. However, uncertainties about climate change predictions and the paucity of knowledge limit our ability to predict potential impacts on plant diseases. Both experimental and modelling approaches are available for impact assessment research. As the development and implementation of mitigation strategies take a long time, more research is urgently needed and we hope this review will stimulate interest.