Crops fall victim to viruses, bacteria, insects, fungi, and exotic organisms like the potato blight that wreaked havoc in 19th century Ireland. Our large chestnut tree are gone from fungal infections and our elms hang on in isolation or heavily sprayed reserves. A virus has wiped out the papaya crop in Hawaii. A fungus threatens the coffee crop of small farmers in Central America. How can society deal with these disasters?
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We have learned to breed resistant crops, and had great success with an older green revolution. We can take other precautions against plant diseases, whether they involve crop rotation or chemicals. Against foreign pathogens, to which native plants have little resistance, the classical tools of plant breeding may not be enough.
There have been many advances recently in the study of infectious diseases of plants and animals. They have given scientists a better understanding of the offensive capacity of the invader and the defenses of the host. Every organism that attacks a plant (or an animal) has evolved methods to subvert the resistance of the host. We are learning what those tricks are and how to counter them. By comparing the DNA of resistant potatoes, say, with the varieties killed by blight, we get a good idea of which genes protect the plants.
Genetic techniques can provide resistance to various pests, including the virus that kills papayas, the blight that ruins potatoes or eventually, the fungal blight that kills our chestnut trees. The same molecular techniques can make rice or sugarcane resistant to flooding or drought or create a strain of rice that makes vitamin A to fight endemic blindness in Asia. There are many other examples. The techniques permanently change the genetic constitution of the plant and therein lies the controversy.
There is visceral and dedicated opposition to GMO crops. Some people feel that the new creations will give rise to unpredictable monsters if released into the environment. That is a worry that biologists don’t usually have. We know the nature of the genes that are being introduced into plant cells, often to unlock normal plant resistance that has been suppressed by an invader. Usually only a few genes are transferred to a plant and they are not involved with making toxins. Millions of genes have now been studied from many species and those linked to human disease are known.
Some people fear that the producers of these crops are giant corporations, like Monsanto, whose motive is profit and not a concern for farmers or the land and a balanced ecosystem. This is a real concern; power corrupts, after all. Part of the answer lies in regulation, part in competition. Some GMO crops are not made by large corporations - the laboratories that made the virus resistant papaya and the blight resistant potato are academic institutions.
A third group feels that God created plants that should not be altered by arrogant scientists. Scientists have little sympathy for the idea that nature is best because nature is seething with parasites of all kinds that consume our food or kill us. People reasonably fear what they do not understand, but with a little study they can understand what is being done and why.
The Economist points out that GMO crops designed to grow in marginal lands could be a great benefit to the poor people who live there, especially in times of climate change. Thirty million children die of starvation or malnutrition each year in areas of the world where people live on less that $2 a day. GMO crops will not reverse this disaster but there is a good argument that they will help reduce that number.
Giving up GMO crops does not return us to The Garden of Eden – it returns us to fungicides, insecticides and plants that die in drought or flood. Papaya farmers have a plant that is immune to the Papaya Ringspot Virus, but an organization to keep Hawai’i GMO free is fighting the new crop. It troubles me when people are casual about other people’s livings, destroying a major cash crop, or increasing the threat to the diets of poor people. Blanket denunciations of all GMO crops reveal passion, but not knowledge.
Like many conflicts in American life, the GMO argument can quickly erupt into anger that sheds no light. Here are questions I ask when thinking about genetically modified crops: What, exactly, is the modification? Does it activate a plant to fight an invader? If successful, will it reduce or increase the use of chemicals? Will it increase the food supply? Who controls the distribution of the plants or seed and what is their attitude toward fair distribution and regulation? Above all, we should ask whether modern agriculture should reject a useful tool in the face of climate change?
