Rust Never Sleeps
A new flare-up in an age-old battle between wheat and a fungal killer
In his quest for world domination, James Bond’s nemesis Ernst Blofeld threatens to unleash a pathogen that would destroy global food supplies. Humankind now faces such a foe. But this villain doesn’t care about world domination, and it needs no evil genius to release it. The fungus known as wheat rust, one of history’s most feared and destructive plant pathogens, is already sweeping the planet. Wheat rust can turn a healthy crop into a black, tangled mess of broken stems and shriveled grains just weeks before harvest.
The battle between wheat and the fungus is an old one: Evidence suggests that wheat rust was a plague during biblical times. In ancient Rome it was considered a numen, a deity demanding appeasement via sacrifices and feasts.
Modern fungicides can fight rust, but the costs and quantities required often outweigh the benefits. So wheat breeders have kept the rust at bay by developing varieties with genes that resist it. For the most part, these breeders have helped wheat gain the advantage over its foe. But perhaps ritualized prayer shouldn’t be completely off the table. An especially virulent form of one type of rust, wheat stem rust, has recently emerged and proved immune to wheat’s genetic arsenal. Estimates suggest that 90 percent of the world’s wheat crop is now vulnerable.