Disarming Farming's Chemical Warriors: Research Brightens the Dark Underside of the Green Revolution
Vaughan, Christopher, Science News
Disarming Farming's Chemical Warriors
The year 1983 proved a landmark for the 168 million people of Indonesia. For the first time in modern history, earth's fifth most populous country, once the world's largest rice importer, succeeded in growing enough rice to feed itself. It accomplished this by pursuing what one expert calls "intensive farming beyond the comprehension of most American farmers."
Yet within the historic feat lay the seeds of serious future problems.
Much of the Indonesian archipelago's 13,677 islands is covered with an emerald-colored patchwork of rice paddies. As part of the "green revolution," the government introduced modern fertilizers, new rice strains and an intricate irrigation system that can control water levels to within an inch, allowing rice farmers in Indonesia to harvest two or three high-yield crops a year.
By 1985, however, this progress was threatened by the notorious wereng, or brown planthopper, which causes rice to dry out, rot and fall in the field. The government, and especially the rice farmers, remembered well the disastrous harvests of 1975 to 1979, when the tiny pest laid waste to 10 million acres of rice--a devastating loss for a country of small farms, where a half acre often must support a family of five.
To prevent the hotspots of brown planthopper infestation from spreading, the government of Indonesia invited the United Nations' Food and Agriculture Organization (FAO) to initiate an ambitious project called integrated pest management, a program started in the Philippines and now being implemented in many countries throughout South and Southeast Asia. Ultimately, integrated pest management could provide the 45 percent of the world's population that lives in South and Southeast Asia with rice-growing techniques that could save developing countries millions of dollars and preserve wildlife and human health without endangering high crop yields.
Integrated pest management teaches farmers to spray very little insecticide on their crop, allowing the field's natural insects to battle it out among themselves whenever the farmer determines that rice-eating insects are at a disadvantage against their predators. The scientific basis for using the technique in Indonesia lay in research done after the 1975-1979 brown planthopper disaster. Scientists found that one of the high-yield farming techniques begun during the green revolution had a dark underside: The pesticides introduced and subsidized by the government to increase yields killed some of the brown planthoppers, but they also killed many beneficial insects that preyed on the planthoppers.
Researchers found that farmers were often spraying their fields habitually -- regardless of whether the fields were infested -- and that such overuse of pesticides actually increased the risk and severity of pest infestation in the rice fields. This and other research indicated Indonesia's need for integrated pest management.
"If left alone, the good insects -- predators -- usually would keep pace with the bad ones and preserve the crop," says FAO Program Coordinator Peter Kenmore. For instance, one wolf spider can eat five to 20 brown planthoppers a day, he says.
But planning a program of integrated pest management was far easier than instituting it among Indonesia's 2.5 million farmers. Many farmers saw the use of pesticides as insurance against the threat of infestation, and with the government subsidizing 75 percent of the cost of pesticides, they often saw little reason to change their farming methods, says Allan Steinhauer, chairman of the entomology department at the University of Maryland in College Park and executive director of the Consortium for International Crop Protection. "You can do everything bureaucratically and politically, but if you can't get the farmers to change you're dead," Steinhauer says. "It takes almost a catastrophe to do that. …