One of the hallmarks of the organic food movement is a wholesale rejection of much of the agricultural technology – particularly biotechnology – that has benefited mankind over the past several decades. For organic foodies, genetically modified (GM) crops remain public enemy #1, in part because they (falsely) believe the crops are bad for the environment.
Just imagine the irony if a scientific study were to discover that merely cultivating GM crops provided a healthy boost to the local ecosystem, including to organic crops.
Well, what do you know? A new paper in Nature does exactly that.
The cotton bollworm is an insect larva that, as its name implies, devastates the cotton plant. There are essentially two ways to control it: Smother a field in insecticides or grow cotton that has been genetically modified with a toxin derived from the bacterium Bacillus thuringiensis (Bt).
For years, the Chinese tried the first approach. However, soaking fields with insecticides is expensive and environmentally damaging. In 1997, the Chinese government switched to Bt cotton as a way to control the bollworm population.
Perhaps unexpectedly, this decision also had a positive unintended consequence: As Chinese farmers began using less insecticide, the population of another insect pest – aphids – began to decrease. How is that possible? Why would less insecticide cause a drop in the population of aphids?
Because insecticides kill indiscriminately, they kill many species that are beneficial to farmers – such as spiders and ladybirds. These predator species feast on aphids. (Yes, those cute ladybugs eat other insects.) Thus, the chain of events goes like this: Bt cotton allows farmers to use less insecticide, which causes predator populations to increase, which then leads to a decrease in the population of aphids. This is a win not only for farmers, but also for the environment.
But, that’s not all. The authors also discovered that Bt cotton conferred a benefit on neighboring, non-GM crops. They found that non-GM crops, such as peanut and soybean, benefited from higher populations of predators, which in turn likely help keep the pest aphid population low. Through a sort of “halo effect,” the mere presence of Bt cotton indirectly helped protect non-GM crops. Again, this is another win for farmers and the environment.
Also, this is not the first time such a “halo effect” has been described. In 2010, a paper in Science showed that Bt corn helped protect non-Bt corn from a pest called the European corn borer. Thanks to genetic modification, farmers in Illinois, Minnesota, and Wisconsin who planted the non-Bt corn were saved $2.4 billion over the course of 14 years.
Increasingly, the scientific data on GM crops is showing a net positive effect on the environment and in the pocketbooks of farmers. Ironically, organic food activists fail to recognize the tremendous environmental and economics benefits of the technology they so vehemently protest against.