Can a Genetically Modified Bug Combat a Global Farm Plague?

Tessnow says it’s important to know more about the genetic structure of the fall armyworm, a project she’s working on during her doctoral thesis. “It will be interesting to see how effective Oxitec’s release GM fall armyworms is on reducing this insect’s population,” she writes.

Oxitec has some experience with producing genetically modified insects. The company began developing a GM mosquito, originally using gene drive technology, back in 2009 to control Zika, a virus passed through mosquito bites, which can cause birth defects in children developing in utero. Oxitec researchers then developed a second-generation mosquito with the self-limiting lethal gene that would only last for a few generations. That mosquito was approved by the Environmental Protection Agency for release this year in the Florida Keys, despite opposition from some environmental groups and local residents, who argued that the agency hadn’t fully considered the effects on human health and the environment.

After its approval by EPA regulators, Oxitec CEO Grey Frandsen said that using the GM mosquito would be both safer and cheaper than spraying chemicals to kill immature mosquitoes that can transmit dengue fever, Zika and other blood-borne diseases. “Our aim is to empower governments and communities of all sizes to effectively and sustainably control these disease-spreading mosquitoes without harmful impact on the environment and without complex, costly operations,” Frandsen stated in a press release issued in May. “The potential for our technology to do so is unmatched, and this EPA approval will allow us to take the first steps towards making it available in the US.”

Oxitec also developed a genetically modified diamondback moth and did field trials in upstate New York in 2017 that used similar self-limiting genetic modification technology to reduce the population of a caterpillar that eats cruciferous crops like cabbage, cauliflower, and broccoli. That project was completed, and showed promising results, but the company decided to switch to the fall armyworm, Morrison says.

Still, not everyone believes introducing a modified insect is the way to combat agricultural pests, including Jaydee Hanson, policy director at the Center for Food Safety, a Washington-based advocacy group that previously opposed the EPA’s decision to release Oxitec’s modified mosquito. After all, Hanson says, the Oxitec program would only kill one of many insects faced by farmers in the developing world, leaving the others to move in. “The problem is when you take a .22 rifle approach and what you need is something that will kill off, in a sustainable way, the other pests,” he says.

Anthony Shelton, a professor of entomology at Cornell University, worked with Oxitec on the experimental release of the diamondback moth in 2017. He agrees that the battle between farmers and pests can resemble an endless treadmill of technological innovation by scientists, immediately countered by fast-breeding insects who evolve to avoid what science throws at them, such as by developing resistance to pesticides. “We constantly have to modify our strategies, because it’s a biological system,” Shelton says. “What we need to do is find strategies that are more durable and more environmentally friendly.”

Both Shelton and Tessnow say that any genetically modified organism must be part of a system called integrated pest management, which includes rotating crops to stymie any buildup of insects on one particular plant, encouraging the growth of the pest’s natural predators, and using limited amounts of pesticides so insects that survive the chemicals don’t get a chance to build up resistance to them.

There’s a lot riding on the potential success of a chemical-free solution to the fall armyworm explosion that has shuttered farms across the world’s tropical zones. “This is a really serious global pest,” Shelton says. “We need to look at all the technologies to figure out what will work so we don’t have this catastrophe in agriculture.”

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