The UK development minister, Andrew Mitchell, is staring down a test tube in a Surrey laboratory. He is looking at a specimen of the fall armyworm, a pest with a voracious appetite that can munch its way through an African maize crop at astonishing speed.
The moth arrived on the African continent from the Americas in 2016, and has spread to 28 countries, gorging its way through maize, wheat and cotton at an alarming rate. Only the desert locust and the brown marmorated stink bug have been more destructive to arable farming.
