Last week, the U.S. Department of Agriculture approved the release of genetically engineered diamondback moths for a field trial in an area of upstate New York. If approved by the New York State Department of Environmental Conservation, this will be the first wild release of a genetically modified insect in the United States, Kristen V. Brown reports for Gizmodo.
Researchers from Cornell University are studying whether the engineered insects could be used to reduce the population of the diamondback moth—a European species that has become an agricultural pest in the United states. Its caterpillars munch cruciferous vegetables, such as broccoli, cabbage, brussels sprouts and radishes, doing some $5 billion in crop damage each year, Eric Niler reports for Wired. Even more troubling, the insect is now resistant to 95 chemical compounds.
As Emily Mullin at MIT Technology Review reports, a U.K. company called Oxitec developed the moths, which will be tested on a 10-acre plot owned by Cornell. The engineered male moths have a “self-limiting” gene, which causes any female moths they father to die before reaching their reproductive stage. The idea is that as the gene will spread among male moths while continuing to kill female moths—and eventually the diamondback moth population will crumble. The engineered moths also have fluorescent protein marker so researchers can identify the genetically modified insects in the field.
While using genes to reduce the insect population is new, the technique of releasing altered males into the population is not. In the 1950s, USDA entomologists Edward F. Knipling and Raymond C. Bushland pioneered the “sterile insect technique.” Screwworm flies used to be a major pest for livestock, laying eggs in the wounds of animals. When they hatched, their maggots would eat the creatures alive. The researchers began irradiating male screwworm flies to make them sterile and released them into problem areas. Since female flies only mate once, they would mate with the sterile males then die. By 1966, the fly was gone from the U.S., though minor cases still pop up.
As Mullin reports, Cornell entomologist Anthony Shelton and his team will release up to 30,000 altered moths per week over the course of three to four months. Because the adult stage of the insect is not a hazard to crops and because New York’s harsh winter will eventually kill the released moths, the USDA determined the release will have no significant impact on crops or the environment. Experiments in greenhouses have shown that the technique is successful in reducing the numbers of diamondbacks.
Not everyone is a fan of the release. Niler reports that while agriculture advocates and those wishing to reduce overall pesticide use support the genetic modification, many environmentalists and concerned citizens object to the idea of messing with natural systems that there is no way don’t completely understand.
Jaydee Hanson, a senior policy analyst at the Washington, D.C.-based Center for Food Safety tells Mullin that even if it works, engineering the moth is pointless. “There are other insects that eat these vegetables. If you will still have to spray the same chemicals to kill other pests, where’s the advantage in this?” he says.
Over the past few years, Oxitec has released engineered mosquitoes in Brazil, Panama and on Grand Cayman island reports Brown. A planned release of mosquitoes in the Florida Keys also received a green light from the USDA, though local opposition has stalled that experiment. The company is also planning on releasing modified Mediterranean fruit flies in Western Australia.