"Wheat is the most widely planted crop in the world, providing a fifth of mankind's calories. So the return of stem rust could cause vast suffering, threatening mass hunger in some of the world's most populated areas," according to the Economist.

A deadly disease that attaches the most popular food source in the world in a time when food prices are jumping, because they are in such short supply, is a major threat. Such a threat would cause prices to spike, but also to limit revenues for existing farms, because supply would shrink.

New wheat technology may help to combat the disease, but the time line is uncertain. …