Adrift Just Off the Islets of Langerhans

The weedkillers atrazine and simazine were introduced in 1958. Ten years later, a plant nursery in the US that had been regularly using the pesticides reported that they were no longer effective against a plant called common groundsel – the first confirmed case of herbicide resistance.

Half a century on, the number of known strains of resistant weeds stands at 357 and counting. “Herbicide resistance is a fantastic example of evolution in response to human-induced selection pressure,” says Stephen Powles of the University of Western Australia in Perth, who studies the problem.