The spread of pests and pathogens that damage plant life could cost global agriculture £400 billion a year if left unchecked, according to a new report published today.
In its annual State of the World's Plants, the Royal Botanic Gardens at Kew said the increase in international trade and weak border controls were causing invasive pests to cause damage to crops.
"Plants underpin all aspects of life on Earth from the air we breathe right through to our food, our crops, our medicines," said Professor Kathy Willis, RBG Kew's director of science.
"If you take one away, what happens to the rest of that ecosystem - how does it impact?"
Potential future costs of controlling plant pests and diseases are on top of the existing spend on the problem, with the EU alone using 196,000 tonnes of pesticides a year against fungi, bacteria and pests such as insects.
Ash trees
Ash trees in Britain are facing a new pest, emerald ash borer, a beetle spreading westwards from Russia, originally found in China, Japan and Korea.
The scientists said the threat is coming at a time when they are beginning to recover from the devastating ash dieback fungus.
Experts have said the emerald ash borer could soon arrive in Britain and wreak devastation in a similar way to US cities, where tens of millions of ash trees across 25 states have withered and died, costing the economy $10 billion.
Dr Richard Buggs, head of plant health at Kew, said the beetle could be the 'final nail in the coffin' for Britain's ash trees.
And Professor Kathy Willis, director at Science at Kew, and editor of the new report said: "It's also about the loss of ecosytems that go with the trees.
"The sad thing is, it's not just that you’ve lost your street furniture, but as a city loses the trees you get an increase in respiratory problems and an increase in mental health problems."
