In Pakistan and India, two of the nations that benefited most from the new crop varieties, grain yields more than quadrupled over the period.

After decades in which they have not encountered the disease most of the world's wheat varieties have fallen behind in the endless battle of thrust and counter-thrust waged by predators and prey.

Nori is certainly the kind of Japanese seaweed that is most familiar in the West, but it is only one of many varieties widely eaten and enjoyed in this country.