Danger: Too Much of One Kind
THE magazine BioScience warned recently: “Another specter, that of a widespread disease epidemic, haunts the ‘green revolution.’” Why is this so?
When large areas of one family of grains are grown, the entire crop is exposed to a serious hazard. Should a new type of insect or plant disease strike, all of the acreage planted in that kind of grain can be affected. But when there is a variety of grain types, that is not usually the case.
Experts agree that this is a distinct possibility with the new, high-yield grains. These new types come from a very narrow genetic base. The Rockefeller Foundation reports that from one particular strain has come the entire family of wheats that today occupies more acreage in Asia than any other type.
Yet, because the new types produce so well, they are given preference. Farmers want to make money. They will plant whatever makes money quickly. So they plant more and more of the high-producing kind and replace the local, lesser-yielding grains. Yet, the new varieties, not having been developed in the local area, have an unknown tolerance for certain diseases.
Because of this an article in London’s New Scientist sounds the alarm: If the few new types were to succumb to a disease, the results would be catastrophic. There would be little to replace them with for a while, as it takes time to develop new strains resistant to a new disease. The article concluded that the possibility of disaster may have been multiplied instead of being decreased by man’s tampering with the natural creation.
Has It Happened Before?
However, is that fear just a theoretical one? Not at all. It has happened before to crops that had too narrow a genetic base.
One example of this was the epidemic that struck potatoes during the last century. It was known as the late blight disease. In 1845 a serious outbreak of the disease was experienced in Europe. That was followed in 1846 by more losses in Europe, and by a disaster in Ireland.
The Irish had turned the bulk of their land to potato production, growing one variety predominantly. The blight devastated this potato crop. The World Book Encyclopedia tells what happened as a result: “The potato famine of the 1840’s caused the worst disaster in Irish history. . . . about 750,000 persons died of starvation and disease. During those years, hundreds of thousands of persons left Ireland.”
A more recent example occurred in this century, about twenty years ago. Oat breeders in the United States began to produce a new high-yielding variety of oats. It involved crosses in an oat family called Victory. These varieties were widely accepted and planted. But then there occurred an increase in a particular fungus that took a high toll of the oat crop. Within two years, this fungus became so widespread that the Victory-type oats could no longer be safely grown.
In the 1930’s a wheat variety was developed called the Hope gene. It promised to solve the problem of losses from stem rust. In a few years whole areas of the western United States, from Texas to North Dakota, were planted in it. But by the late 1940’s a new and highly virulent fungus arose. All the bread and durum wheat grown in the United States, and Canada, was susceptible to it. The new fungus spread rapidly in the major wheat-growing areas and took its toll. For several years it resulted in the near halting of durum wheat production in the Northern Great Plains.
Most Recent Setbacks
In 1971 the New York Times carried this headline: “A Triumph of Genetics Threatens Disaster.” The accompanying article told about the improved types of hybrid corn introduced in the United States since 1950. These had more than doubled the corn yield per acre.
But then, in 1970, there came an unexpected attack by a new virulent disease called the southern corn leaf blight. It exposed the vulnerability of the specialized corn planted by most farmers. Between July and harvesttime in 1970 about 700 million bushels of corn were destroyed! That was 15 percent of the entire corn crop, worth about one billion dollars!
Of this corn disaster, the New York Times commented:
“The basic vulnerability arises from the fact that all farmers want to plant the best varieties of each crop at the same time. The resulting uniformity threatens disaster when some new mutant enemy—like the latest variety of southern corn leaf blight—appears.
“As in so many other areas of the modern world, that which makes short-run good sense economically poses serious long-run problems, both ecologically and economically.”
However, have any of the newest grain varieties suffered this way? Yes. Already the new rice has been affected. In the book The Environmental Crisis it was noted: “Already IR-8 rices have had a lot of trouble from this problem, but even bigger monocultures are being created.”
A “monoculture” is the growing of a single crop and generally not using the land in any other way. So although trouble is being experienced, even larger monocultures of the new grains appear to be the rule because farmers want to make money quickly.
In February of 1972, new figures were released from the National Food and Agriculture Council about the situation in the Philippines. They showed that a deadly plant virus called tungro had blighted some 140,000 acres of riceland in Luzon and in Mindanao. President Ferdinand Marcos told the Philippine Congress: “It was a disastrous year  for Philippine agriculture.”
Because of the new high-yield rices planted after 1966 the Philippines had experienced self-sufficiency and a small surplus up to 1970. But last year, 1971, huge imports became necessary—460,000 metric tons of rice. And the government predicts that the country faces a vast shortage of nearly 640,000 metric tons in 1972 and about the same in 1973.
So planting larger and larger areas of a crop with too narrow a genetic base is a very dangerous procedure, and shortsighted. But that is not the only problem connected with the new grains.
[Picture on page 6]
The contrast between blighted hybrid corn (right) and unaffected, open-pollinated corn (left)