In a report released by the Intergovernmental Panel on Climate Change in 2007 it concluded that global warming is occurring and that changes in the global climate system will continue into the future. These changes including higher average temperatures and higher levels of carbon dioxide in the atmosphere which are expected to have a major impact on agricultural systems. However, there is a lack of empirical data on the effects of elevated CO2 and temperature on agricultural pest and pathogen populations. Consequently, predictions on the future of our major crops such as wheat have not been fully explored.

The Department of Primary Industries Victoria, the University of Melbourne and the Department of Climate Change have established a Free-Air CO2 Enrichment (FACE) research facility at Horsham, to study the effects of elevated CO2 on wheat production in Australia. This facility is being used to study the effects of elevated CO2 (550ppm) under field conditions on wheat, the Barley yellow dwarf virus (BYDV), as well as biology of its aphid vector Rhopalosiphum padi (Homoptera, Aphididae).

Results from studies on wheat plants conducted at the FACE facility show changes in C:N ratio, increase in plant height, biomass, number of tillers, and surface area in response to elevated CO2. However, variable field conditions have proved difficult for studying the impact of elevated CO2 on BYDV and its vector, therefore in addition to the FACE facilities, controlled environment growth chambers are being used to study the physiology and feeding behaviour of R. padi and its ability to acquire and transmit BYDV under various climatic conditions and CO2 concentrations. Results from the FACE facility and growth chambers will be described and presented. Potential ecological and epidemiological consequences will be discussed.