Global risk levels for corn rusts (Puccinia sorghi and Puccinia polysora) under climate change projections

Common rust (Puccinia sorghi) and southern rust (Puccinia polysora) are two of the most important foliar corn diseases worldwide. These fungi have caused severe economic loss to corn yields worldwide. The current and future potential distribution of these diseases was modelled with CLIMEX using the known current geographic locations of the rusts, growth and stress indices. The models were run under the A2 scenario using CSIRO-Mk3.0 and MIROC-H for 2050 and 2100. The current projection shows areas with marginal to optimal suitability in all the continents. The models for future projections display a general reduction in the Southern hemisphere and increase in the Northern hemisphere, especially for the southern rust. The overlay of the General Circulation Models produce an estimation of the common areas under risk for future climate conditions for the simultaneous occurrence for both corn rusts, with a reduction of the medium- and high-risk categories by 2100. This study highlights the possible effects of climate change at a global level for common and southern rust, as well as the risk of occurrence of both diseases in common areas for future climate that could be particularly harmful for crops.