Cornell’s sustainable pest control pioneer weathers storm over GMO moth experiment

By Joan Conrow

September 5, 2017

Like Rachel Carson, his inspiration for studying eco-friendly insect pest management, Cornell University Professor Tony Shelton has encountered controversy in his academic career.

Carson, a biologist who published the pioneering 1962 environmental creed Silent Spring, was subjected to fierce criticism from chemical companies for challenging the widespread, indiscriminate use of pesticides and documenting their unintended consequences on the natural world.

Shelton, whose passion for entomology and food security was sparked by Carson’s book, has been excoriated for trying to carry out a vision she articulated in her final chapter, where she wrote about sustainable alternatives to the use of broad-spectrum insecticides.

“She advocated using very narrow-range tactics to control insect pests, including insect pathogens, biological control and even the drive of an insect’s life forces,” Shelton recalled during a recent conversation at Cornell University’s New York State Agricultural Experiment Station in Geneva, NY. “That idea fascinated me, that we could use biology to control a pest, instead of insecticides.”

Specifically, Carson wrote: “Some of the most fascinating of the new methods are those that seek to turn the strength of a species against itself, to use the drive of an insect’s life forces to destroy it. The most specialized of these approaches is the male sterilization technique.”

Carson anticipated the intense opposition to her work, and time has proven her right on many of the issues she highlighted. Shelton also knew full well what he was getting into. Still, he admits to being disappointed by the misinformation directed at his research to find a non-insecticidal control for the diamond-backed moth (DBM). The voracious pest devastates cabbage, New York’s most valuable crop, and annually causes some $4-to-5 billion in damage globally.

It also rapidly develops resistance to insecticides — sometimes in less than two years, Shelton said. “I wondered, are there other tools we can use that are biologically based and effective?”

The strategy of sterile moths

As befits a scientist, Shelton turned his wondering into a research project. He is now testing a self-limiting DBM developed in collaboration with Oxitec, a British company that has used the sterile insect technique to control disease-carrying mosquitoes in Brazil. The moths, bred in a laboratory, carry a sterility gene that is passed on to their offspring when they mate with a wild female. The resulting female offspring do not live long enough to reproduce, thereby naturally suppressing the pest population.

The sterile insect technique has been successfully used to help control livestock pests like the screwworm in America and the tsetse fly in Africa. But those early efforts used radiation to achieve sterilization, while Shelton’s work employs the more precise tool of genetic engineering. This has put him and Cornell University squarely in the cross-hairs of anti-GMO activists opposed to his cutting edge research.

“There have been many advances in agriculture from pasteurization to hybrid crops that were initially controversial, but are now mainstream,” said Shelton prior to an Aug. 16 public meeting on his plan to release the self-limiting moths in an isolated cabbage field on Cornell s research farm to test their performance in an agricultural setting. “We are trying to develop innovative methods of crop protection that don’t involve insecticides that harm farm workers, beneficial insects, pollinators and the environment. This approach seems like a win-win.”

A Cornell cabbage field is the site of the GE moth trials. 

Although still in the experimental stage, early results from greenhouse and caged field trials were promising. The research has tremendous implications for environmentally sustainable pest control, both in the agricultural and health sectors — assuming the hostility from anti-GMO activists can be overcome.

An ardent sailor, Shelton surely would have preferred to spend his summer free time sailing on nearby Seneca Lake. But he’s had few spare moments in recent months as he manages the experiment and deals with the pressure of responding to the considerable controversy swirling around his project.

Controversial GM technology

Biotechnology is a hot-button issue, and Shelton knows that addressing public concerns comes with that territory. He has been doing outreach for the past three years, creating an informational website, delivering lectures and hosting a 2015 public forum. Even so, neither he nor Cornell seemed to anticipate that the first open release of genetically engineered self-limiting insects in America would become such a big story.

The Geneva forum was yet another attempt at engagement, attracting a smaller crowd than expected and fewer foes. Shelton knows many of his local opponents because he previously helped them resolve pest problems on their organic farms. He recognizes that some of them are worried about how GE insects could affect their organic certification, but he says the legal precedents don’t support their fear.

Despite the meeting’s amicable tone, Shelton was already feeling the strain of countering attacks on his research. He’d just weathered the 30-day public comment period on his application for a federal permit to release the insects. After 16 months of intense scrutiny, the US Department of Agriculture issued a Finding of No Significant Impact and granted permission for the confined field trials.

Still, the process generated a flurry of controversy that made clear Shelton’s opponents suffered from some grave misperceptions about his research. Part of the problem stems from ideological blinders that prompt many activists to dismiss any GMO work out of hand, regardless of the details. But some of it was due to lack of resources and time and the inherent difficulty of communicating science to the public.

Scientists typically don’t talk about their work until the research is completed and published in a peer-reviewed journal. And universities typically don’t need to defend scientifically sound research under way at their facilities.

But anti-GMO activism has upended those traditions, leaving scientists and university administrators scrambling to figure out how to respond. Putting biotech research in the hot seat is a tactic activists have intentionally employed; if it becomes too uncomfortable, they figure, the research will be dropped.

Reaping biotech benefits

Though wearied by the work and the conflict, Shelton has no intention of giving up. A world-renowned expert in sustainable agriculture, he has already seen the benefits of genetic engineering first hand. As project director for the USAID Feed the Future South Asia Eggplant Improvement Partnership, Shelton has collaborated with scientists at the Bangladesh Agriculture Research Institute and Bangladesh Department of Agriculture Extension to develop insect-resistant tBt brinjal, which has helped Bangladeshi farmers dramatically reduce their pesticide use.

He recalled that recently, while standing in a field in Bangladesh, a farmer told of how growing Bt eggplant had allowed him to go from using 100 sprays a season to just two.

Shelton also has been at the forefront of Integrated Pest Management (IPM), a technique embraced by the agro-ecology movement because it uses insecticides as the last line of defense against pests. One of his mentors in graduate school had developed the concept of IPM three years before the publication of Silent Spring. Shelton sees self-limiting insects as a natural extension of IPM, a view echoed by Professor Jan Nyrop, director of the Geneva research station.

“Cornell is committed to developing more sustainable methods of controlling the pests that attack our crops,” Nyrop said at the Geneva public meeting. “That is the goal of our work with the diamondback moth.”

As Shelton’s experiment proceeds, he remains clearly frustrated by opposition that seems grounded in pure ideology and lack of scientific understanding.

Still, his undergraduate training in philosophy and the classics allows him to appreciate the irony of environmentalists opposing an environmentally sound approach to pest management first championed by his own environmental hero, Rachel Carson. After all, he’s an environmentalist, too.

“I got into this to try and make a difference in the world,” Shelton said. “That’s what keeps me going. But frankly, this conflict is taking some of the joy out of the work.”