Climatic changes and the potential future importance of maize diseases: a short review

Abstract

This mini-review summarizes the existing knowledge and hypotheses on the potential changes to the future importance of maize diseases due to projected global climatic changes. In contrast to fungal pathogens, there is almost no information available on viral and bacterial diseases. Most studies related to fungi refer to Aspergillus and Fusarium species, which are causal agents of maize ear rot, and the related risk of mycotoxin contamination of maize grain, potentially harmful to animals and humans. Just a single long-term simulation study based on a modelling approach driven by a climate change scenario has been reported for a maize disease so far. It projects a reduced risk of Puccinia polysora (southern rust) occurrence in Brazil in this century. More simulation studies, ideally those which also generate quantitative disease-yield loss data for different maize diseases and locations are certainly needed in order to include the future potential disease risk in maize to the climate change debate. This will enable the estimation of the future maize productivity based on both abiotic factors such as temperature and biotic factors such as diseases. A fundamental conclusion of this mini-review is that global maize disease problems caused by a changing climate will probably not consistently worsen, because climatic changes may also improve the crop health situation in maize depending on the disease, location and time scale considered, although ear rots and associated mycotoxin contamination of maize grain are expected to increase in many countries worldwide. Reducing ear rot disease risk is already of high priority and will likely demand particular attention in the future as well.