Like Oxitec’s mosquitoes, its diamondback moths are genetically engineered to be self-limiting. Shelton is releasing males carrying a lethal gene that eventually kills all female offspring. Over time, the males will have no one to mate with.

The diamondback-moth release, too, has its critics. The U.S. Department Agriculture’s decision to allow the field trial got hundreds of comments, many of them brief but angry. “DO NOT PERMIT! Future ramifications are unknown and could be dangerous to the entire world,” reads a typical comment. The Northeast Organic Farming Association of New York also criticized the decision due to fears of the genetically engineered moth spreading to their organic crops.

For the scientists, however, this field test is the next logical step after experiments in greenhouses and field cages. Shelton says it’s unlikely the moths will spread because of the remote location of the cabbage plot. Still, he’s installed traps to track how far the engineered moths can fly.

“Undoubtedly this has been the most—how should I say it—paper-intense project that I’ve ever undertaken,” says Shelton, who first heard about Oxitec’s genetically engineered insects about eight years ago. He says he’s been extra careful because of the scrutiny that comes with the first U.S. release of genetically engineered self-limiting insects. “Scientists want to be the first to do something,” says Shelton. “In this particular case, I would have loved to be the second.”

There is precedent, of a sort, for releasing sterile insects for pest control. From the 1950s to the early 2000s, a massive effort went into eradicating invasive screwworms—which burrow into the flesh of livestock—from the United States down to Panama. That campaign used screwworms raised in a factory and bombarded with radiation, which damaged their DNA so much as to make them sterile.

Then, beginning in 2006, researchers tested irradiated and sterile pink bollworms—also from Oxitec—in cotton fields in Arizona. These bollworms had been genetically modified to carry a fluorescent protein, which marked them as the company’s. That was the first release of insects with any sort of genetic modification in the United State. The general sterilization-by-irradiation strategy has also been used to control the Mediterranean fruit fly and the Mexican fruit fly.

The diamondback moths are not irradiated, though, because the irradiation strategy didn’t work. Shelton tried that back in the 1990s. “You could sterilize them, but they were not very fit. They couldn’t fly,” he says. The radiation had damaged them too much. Genetic engineering is a more precise way make the moths unable to viable offspring, leaving them still fit enough to fly and mate.

Scientists are watching the diamondback moth trial closely. “I’ll be very interested to see if this thing succeeds,” says Fred Gould, an entomologist at North Carolina State University. In addition to diamondback moths and mosquitoes, Oxitec has a handful of other genetically engineered insects that can be used to tackle common pests: the Mediterranean fruit fly, the Mexican fruit fly, and the olive fly.