A Looming Threat to World Food Supply?

By David L. Brown

What would happen if our world, supporting a bloated and still growing population on the slender legs of a few monocultural crops, should be faced with a pandemic? No, I’m not talking about avian flu or any other animal or human disease, but a potential pandemic of plant disease that could attack a major food source.

According to recent statistics, cereal grain crops — primarily wheat, rice and corn (also known as maize) — provide 47 percent of the calories consumed by human beings worldwide, and 42 percent of protein. That’s right, cereal grains and mostly from just three crops, account for nearly half of the nutrition that supports more than 6.5 billion people.

And because of the intensive plant breeding that has produced the high-yielding varieties that made the Green Revolution possible, most native plants with their differing qualities of disease resistance have been replaced by one-size-fits-all varieties. That leaves a disproportionate amount of the worldwide grain crop potentially susceptible to a pandemic of disease that could spread from nation to nation with disastrous effects.


Is it reasonable to think that such an event could happen? Well, if you are familiar with the Irish Potato Famine of the 1840s you have some idea of the possibilities. In the early 1800s, Ireland depended on its potato crop much as the entire world today relies on wheat, rice and corn. In the late summer of 1845 a fungus or blight appeared which almost completely destroyed Ireland’s precious crop of spuds.The blight had a devastating effect on the Emerald Isle, which had a population of only about eight million when the famine struck. The crisis continued for several years, resulting in an estimated half-million deaths, displacement of two million Irish refugees, and the emigration of about another two million to other countries such as the U.S. and Canada.

But that was just in one small country, and affecting a crop that was none too important in most other parts of the world. What would happen if something similar should overtake one of the world’s major food grains? In fact, you may not have read about it in your daily paper or seen it on CNN or network news, but something like that is facing the “Staff of Life,” wheat, right now, and it could become a full-blown disaster of worldwide proportions.

The danger is from a strain of wheat stem “rust,” a disease that can destroy entire crops. Known as Ug99, this new disease was first identified in Uganda in 1999 (thus the name) and is now spreading across East Africa. According to a statement from the International Maize and Wheat Improvement Center, “it is only a matter of time before it reaches across Saudi Arabia and into the Middle East and South Asia, and eventually East Asia and the Americas.”

So how serious could this be? Well, read these ominous words from the current issue of The Furrow, a magazine for farmers published by the John Deere Company:

“Stem rusts like Ug99 are catastrophic diseases because they cause complete annihilation of wheat crops over wide areas,” says Norman Borlaug, Nobel Prize winner and father of the Green Revolution. “The prospect of this disease becoming an epidemic in Africa, Asia and the Americas is real and must be stopped before it causes untold human suffering.”

Last winter Borlaug joined other plant scientists from 18 countries in Kenya to address the problem at an event called the Global Rust Summit. A report from the meeting states that because Ug99 “has broken down the source of stem rust resistance that has protected much of the world’s wheat for 30 years, the crop is poised for an epidemic to spread like wildfire.”

According to The Furrow article, Ug99 can defeat a gene called Sr31, originally found in rye and transferred to wheat by plant breeders to develop Green Revolution crops now grown around the world. In a recent screening of about 2000 U.S. varieties by the US Dept. of Agriculture research station at Beltsville, MD, more than 70 percent proved to be vulnerable to Ug99, including 82 percent of spring wheats, 69 percent of hard winter wheats, and 73 percent of soft winter wheats. Data from Canada shows that the majority of about 100 Canadian wheat varieties are also susceptible.

And even worse, the problem doesn’t stop with wheat — it turns out that many varieties of barley and oats are also subject to infection with Ug99. Nor is the new stem rust the only disease threatening the world’s wheat crop. According to The Furrow article, threats from related diseases called stripe rust and leaf rust “also loom large.”

Plant scientists and seed producers are running scared to find resistant varieties before a global pandemic can become a reality. Meanwhile, proven Green Revolution seedstocks can no longer be counted upon and alternates not only may yield less, but could prove to be vulnerable to other diseases.

In a world that has become so dependant upon cereal grains, the idea of a plant disease pandemic is unsettling indeed. Already we have seen the steady spread of avian flu, which although it may never morph into a human pandemic is already destroying another major source of protein in human diets, that obtained from chickens and other domestic fowl. With both animal and plant sources of food under threat, widespread famine is a real possibility.

How serious could such an event be? Using the Irish Potato Famine as a model, what if a disaster of similar proportions should strike the entire world today? One-eighth of the Irish people starved to death. In today’s world, that would represent more than 800 million deaths. Besides that, two million Irish became refugees, and another two million emigrated. Those figures cannot be extrapolated, because there would be no place for fully one-half of the world’s population to go.

The preceding comparison is no doubt far-fetched, but it does provide some indication of just how serious a major disruption of the global food supply could be. With both avian flu and the new threats to cereal grains on the prowl, the world could soon face some real difficulties, possibly causing our era to be described in future histories as a time of great famine.

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