A new study has shown the spread of crop pests towards the North and South Poles is increasing as the planet warms, leading to more concerns over the future of global food security.

Researchers from the University of Exeter and the University of Oxford have revealed that plant-decimating bugs are spreading at a rate of nearly 3 km a year, the report showing a strong relationship between increased global temperatures in the past 50 years and expansion of the range of crop pests.

The report says that currently, 10 to 16% of global crop production is lost to pests including fungi, bacteria, viruses, insects, nematodes, viroids and oomycetes.

As the diversity of crop pests expands, new strains are continually evolving. The loss of major crops to fungi equates to an amount that could feed nearly nine percent of today's population.

Dr Dan Bebber from the University of Exeter said: “If crop pests continue to march polewards as the Earth warms the combined effects of a growing world population and the increased loss of crops to pests will pose a serious threat to global food security.”

Professor Sarah Gurr from the University of Exeter (previously at the University of Oxford) said: "Renewed efforts are required to monitor the spread of crop pests and to control their movement from region to region if we are to halt the relentless destruction of crops across the world in the face of climate change."

One of the most prominent new threats to the world’s food stocks is the rice blast fungus. Rice blast is present in over 80 countries and has a dramatic effect on agricultural economy and ecosystem health. Alarmingly, it has now moved to wheat; considered a new disease - wheat blast is sharply reducing annual yields in Brazil.

The study was based on published observations of the distribution of 612 crop pests collected over the past 50 years. It revealed that the movement of pests north and south towards the poles and into previously un-colonised regions, corresponds to increased temperatures during that period.

The study has been published in the journal Nature Climate Change; more information is available in an accompanying description by the authors.