Researchers found farmers raising “Bt” cotton, which is modified to produce an insect-killing protein, had 24 percent higher yields, and 50 percent higher profits, than farmers growing conventional cotton.
Critics say the benefits may not last long, as other insects become bigger problems in farmers’ fields.
The debate has global implications for small-scale farmers in the developing world.
Millions of Indian farmers raise cotton on a hectare or two of land and subsist in poverty on $1 or $2 a day.
Fighting the cotton bollworm
Before Bt cotton arrived in India in 2002, farmers relied on chemical insecticides to control an insect pest called the bollworm.
“The types of chemical insecticides that farmers use against the bollworm are among the most toxic ones,” says agricultural economist and study co-author Matin Qaim at Germany’s University of Goettingen. “And they spray quite a bit.”
Bollworms also threaten U.S. cotton crops. So biotech and seed company Monsanto genetically modified cotton plants to produce their own insecticide, a bacterial protein called Bt.
While organic farmers have sprayed Bt on crops for decades, many cotton growers worldwide are now using the genetically-modified, insect-resistant Bt cotton variety of the plant.
Three-quarters of U.S. cotton and 90 percent of Indian cotton are now Bt.
Less control, higher price
But biotechnology critics say farmers are giving up too much control over their seed supply to multinational corporations and becoming increasingly dependent on corporate-controlled technologies.
Bt seeds are more expensive than conventional seeds. Opponents say farmers buying them are going deeper and deeper into debt, driving some to suicide.
But Qaim says his new study shows the opposite.
Improved standard of living
The study examines 533 cotton-growing families between 2002 and 2008.
Compared with conventional farmers, Bt cotton growers are “increasing their effective yields because of lower crop damage,” Qaim says. “And that leads to higher family incomes and that leads to higher living standards, [which] leads to escape from poverty.”
Bt farmers had 18 percent higher family expenditures, suggesting an increase in their standard of living.
“Most of the public believes that GM crops developed by big companies…would worsen the situation of small farms and poor households,” he says. “And I think it is time to reconsider those types of prejudices.”
Research by Washington University anthropologist Glenn Stone has also found increased yields among farmers raising Bt cotton.
However, he says, “It’s frequently the case that new agricultural technologies have positive impacts at first. But, what we really have to be concerned about is how sustainable impacts are going to be.”
Stone says other pests besides the bollworm are now becoming bigger threats, requiring more insecticides.
That may undermine the advantages of Bt cotton – and continue the debate over the risks and benefits of genetically modified crops.