THE threat of diseases such as influenza or tuberculosis re-emerging in virulent form has been a common theme in recent years. That threat is not limited to human diseases. Our food plants gets sick too, and just as human diseases evolve to evade antibiotics, so the diseases that strike our crops evolve to sidestep the resistance genes we have bred into them. For the vast majority of the calories the world eats, the key crop is grain.
A ruinous wheat disease we haven’t had to worry about since the 1950s is making a comeback, and unless we are very lucky,…
