1 DPI, BioSciences Research Division, 621 Burwood Highway, Knoxfield, Victoria, 3180, Australia
Global climate change threatens world food production not only via direct effects on plant growth but also by alterations to pest and pathogen prevalence and distribution. Complex relationships between host plant, pest, pathogen and environment create uncertainty particularly involving pathogens vectored by an insect pest. We attempt to improve the understanding of the effects of climate change on such systems via a detailed review of one crop-vector-pathogen system. The bird cherry-oat aphid, Rhopalosiphum padi, is a global pest of cereals and vector of yellow dwarf viruses that cause significant crop losses in cereals. Rhopalosiphum padi exhibits both sexual and parthenogenetic reproduction, alternating between crops and other host plants. In Australia, where only parthenogenesis occurs, due to the absence of the primary host, the aphid continuously cycles from grasses to cereals allowing for continuous virus acquisition and transmission. We have reviewed the potential impact of future climate projections (increasing temperatures, elevated CO2, altered weather patterns) on R. padi population dynamics, persistence and abundance and the timing, rate and extent of dispersal and migration events. We also looked at the interaction between vector, virus, crop and environment, all of which are critical to the development and behaviour of the vector and its ability to transmit the virus. We identify a number of knowledge gaps that currently limit efforts to determine how this pathosystem will function in a future climate.