Crop pests spreading polewards under global warming 7 November 2013 Issue 349 Subscribe to free weekly News Alert Source: Bebber, D. P., Ramotowski, M. A. T. & Gurr, S. J. (2013). Crop pests and pathogens move polewards in a warming world. Nature Climate Change. DOI:10.1038/NCLIMATE19 90. Crop pests and pathogens are moving into new habitats, towards the North and South Poles, as global warming progresses, new research suggests. Observation records from around the world show that many crop pests, including insect and bacterial pests, are moving towards the poles at an average rate of 2.7 km per year. Today, 10-16% of growing crops are lost to pests, with further losses occurring after harvest. In our globally connected world, there is great opportunity for pests to be spread across international borders. Indeed, it is estimated that more than half of plant diseases are spread by human introduction. However, once introduced, weather conditions are thought to be the main determinant of whether a pest or pathogen becomes established. The importance of weather has led to speculation on how the effects of climate change might affect pest distributions and, subsequently, food security. Contact: s.j.gurr@exeter.ac.uk, d.bebber@exeter.ac.uk This study suggests that the warming climate is allowing pests to become established in regions that would have been previously unsuitable because they were cooler. The researchers analysed 612 published records of where crop pests and pathogens have occurred, including mites, aphids, fungi, bacteria, beetles, flies, butterflies and moths, amongst others. The latitude of occurrences was then plotted to investigate how ranges of these species have shifted since 1960. Read more about: Climate change and energy, Agriculture The results show that, although there was a large amount of variation between different groups, on average, there was a shift of 2.7 km per year towards the poles, with significant shifts for many important pest species. For example, fungi, bacteria, beetles, flies, butterflies and moths have all clearly been moving towards the poles in the past 50 years. The contents and views included in Science for Environment Policy are based on independent, peer-reviewed research and do not necessarily reflect the position of the European Commission. To cite this article/service: "Science for Environment Policy": European Commission DG Environment News Alert Service, edited by SCU, The University of the West of England, Bristol. One important factor that the researchers investigate is the possibility of a bias in the records of where pests and pathogens have occurred. They highlight the fact that scientific techniques and equipment are typically more advanced in countries at higher latitudes, i.e. closer to the poles. However, if such a bias existed it would lead to pests being first reported in countries closer to poles and only later discovered nearer the Equator. The trend observed in this study is that most pests are actually observed first nearer the equator and only later at higher latitudes, suggesting that it is the result of global warming, not data bias. In fact, the only groups that might appear as if they have moved towards the Equator, according to the observation records, are nematode worms and viruses. These are often both soil borne, and therefore more difficult to detect, especially in countries closer to the Equator with less technical capacity. In these cases, it may be bias in the data that explains the apparent ‘movement’, suggest the study’s authors. Although global food security depends on a variety of different interconnected factors, plant diseases and pests can have a drastic effect, especially in poorer countries. The findings in this study suggest that, in the face of climate change, increased investment in monitoring and preventing the spread of crop pests are needed.