Growing crop pest numbers threaten global food security

Rising numbers of crop pests and pathogens pose a grave threat to global food security, according to a study led by the University of Exeter.

The study, published in the journal Global Ecology and Biogeography, warns that if pests continue to spread at their current rate, the world’s biggest food producing countries – including the UK – will be overwhelmed within the next 30 years.

Professor Sarah Gurr told Farmers Weekly that modelling work had showed pests and pathogens were moving 8km a year northwards and a significant number of countries could be “saturated” with pests by the middle of the century.

More than 10% of all pests have already reached more than half the countries that grow their hosts.

“They are on the march towards the poles,” she said. “We also expect to see new species and new variants of old species emerge.”

For UK growers, the biggest threats would be septoria leaf blotch, new leaf spot fungi that are expected to come in over the next decade and powdery mildews, she said.

Potato growers would have to contend with greater problems with potato cyst nematodes and new variants of late blight.

While farmers were planting cultivars of potato resistant to late blight, the organism was mutating to overcome this resistance, she said.

Prof Gurr said the study showed most countries were currently underreporting the loads of pathogen and pests on their crops.

The only country thought to be accurately reporting the level of pathogens was the USA.

“We are all transfixed by disease such as Ebola, but we should also be looking at whether we will have food to eat,” said Prof Gurr.

She called for more research to understand the lifecycles of pathogens, so new systems could be developed to interfere with them.

Dr Timothy Holmes, head of technical solutions at CABI’s Plantwise knowledge bank, added: “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.”