Within 30 years, it's likely that farmers will be battling deadly crop pests that they've never seen before. Pests are evolving and entering new regions in greater numbers than ever — and our worst adversary is likely to be fungus, which could destroy whole harvests and wreak havoc with our food supplies.

Blumeria photo by agronom

A study published earlier this month in Global Ecology and Biogeography suggests that climate changes and invasive species will dramatically increase the number of crop pests in coming decades. The researchers, led by University of Exeter bioscientist Dan Bebber, say that likely we'll be seeing more of three types of pests: nematodes, or roundworms, that attack plant roots; the Blumeria graminis fungus that attacks wheat and other cereals, reducing them to a mildewy mess; and a virus that attacks citrus fruits like oranges.

But it's the fungus the researchers worry most about. That's because it's already living comfortably in a number of areas throughout the world, so it only needs to spread its range a little bit in order to invade new territories and lay waste to them. Other pests may be more numerous, but they'll have to travel farther to do damage.

If we don't take precautions soon, farmers may be faced with wheat fields that have been corroded by a white, chalky fungus (see image above) that they never expected to find.

In a release about the discovery, University of Exeter explains the researchers' methods, which include looking at historical records to understand the spread of pests over time:

The study looked at the current distributions of 1,901 crop pests and pathogens and historical observations of a further 424 species. Significant use was made of historical CABI records, which document crop pests and diseases around the world from 1822 to the present day.

Dr Timothy Holmes, Head of Technical Solutions at CABI's Plantwise knowledge bank, said: "By unlocking the potential to understand the distribution of crop pests and diseases, we're moving one step closer to protecting our ability to feed a growing global population. The hope is to turn data into positive action."

It supports the view of previous studies that climate change is likely to significantly affect pest pressure on agriculture, with the warming Earth having a clear influence on the distribution of crop pests.

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University of Exeter bioscientist Sarah Gurr, who also worked on the study, said that part of the problem is that the fungus and other pests will keep evolving as they spread:

New, virulent variants of pests are constantly evolving. Their emergence is favoured by increased pest population sizes and their rapid life-cycles, which force diversified selection and heralds the appearance of new aggressive genotypes. There is hope if robust plant protection strategies and biosecurity measures are implemented, particularly in the developing world where knowledge is scant. Whether such precautions can slow or stop this process remains to be seen.

The idea is that if we can prepare for these pests before they hit, we are in a much better position to save our crops. This is especially important in the developing world, where many crops are likely targets.

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Read the full scientific paper at Global Ecology and Biogeography