Short Wave - Too Much Of A Good Thing: The Cautionary Tale of Biotech Crops

Episode Date: December 1, 2020

Some of the most popular agricultural biotech products are running into problems. These plants have been genetically modified to fend off insects, and have been great for the environment and for farmers. But now they are not working as well. NPR food and agriculture correspondent Dan Charles explains the rise and potential fall of Bt crops, and what happens when farmers use too much of a good thing.Before the year comes to a close, show your love for Short Wave and your local public radio station by making a donation today! Just go to donate.npr.org/short to get started. See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

Hey, Maddie Safaya here. And Emily Kwong. And today, NPR is launching its annual fundraising competition. No, don't you mean annual fundraising campaign? I mean, yeah, sure, if you want to lose or whatever. That is. See, this fundraiser is a informal competition to see which podcast can drive the most donations to NPR member stations. And because today, December 1st is giving Tuesday, and we are both very competitive.

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That is my girl right there. Here we go. You're listening to Shortwave from NPR. Hey nerds, Maddie Safai here with NPR correspondent Dan Charles. Hi, Dan. Hi, Maddie. What do you got for us today? I would like to introduce you to somebody. Her name is Julie Peterson, and she is an entomologist at the University of Nebraska.

I definitely considered myself kind of a environmentalist sort of thinker and was really interested in ecology, and I fell in love with insects. And when she started grad school, she started looking at something that farmers were doing to fight back against some of their big insect pests. they were planting crops that have been genetically modified, GMOs. And her initial feeling was this is maybe not a good thing, messing around with nature like this. And I sort of went in thinking, oh, these GMOs, these are bad things for the environment. Hmm. Like, and by GMOs, she means crops like corn or cotton,

but where companies have spliced in some genes that help the crop survive or thrive in some way. Right. Now, Julie's skepticism came from a kind of general feeling that it's just risky, maybe ecologically, to move genes around from one species to another one. But then she started to research something called BT crops. These were like the original GMOs. They were not the first ones invented, but they were the first ones to be widely embraced by farmers, starting in the mid to late 1990s. They actually protected themselves from certain insect pests. And the more that Julie learned about these BT crops, the more she started to think, you know, these GMOs might not be so bad after all.

I really started to realize that there's a pretty good scientific consensus and a lot of really good evidence that these risks are quite small, particularly when we compare them to using, you know, more broad spectrum insecticides. And, you know, my thoughts on BT crops really changed. Yeah, so that was the big benefit. They were replacing the use of insecticides that farmers spray, which is good for the whole ecosystem. I feel a butt coming on, Dan. What's the butt? There is a butt. Yeah, there has always been this worry that the BT crops would stop working because of what scientists call resistance, that insects would evolve and become immune to the BT.

And that is what's happening, Maddie, in a big way. And our friend Julie is right in the middle of trying to figure out what to do next. So today on the show, the rise and possible fall of BT crops, what happens when farmers use too much of a good thing? I'm Maddie Safaya, and you're listening to Shortwave from NPR. All right, Dan. Let's start with a little BT Crops 101. All right. Walk us through how they work. So these genetically modified plants got their superpowers from a.

bacteria. Let's let Julie describe it a little bit. For BT in particular, they express genes that come from a type of bacterium. It's really a very common bacteria that's found in soils. It's called bacillus thuringensis as the scientific name. Now, this kind of bacteria is actually poisonous in the larval stage of some major insect pests like corn root worm and cotton bull worm, which farmers worry about a lot. So what the scientists did was they took some of the genes from the bacteria and inserted them into these corn and cotton plants, which then made the plants poisonous to the insects,

just like the bacteria were. So now the plants could actually protect themselves by killing off pests that try to eat them. Exactly, which is a big deal for farmers. Here is David Curranes. He's an entomologist at Texas A&M University. He gives farmers advice on the best way to handle their insect. problems. A lot of them are cotton farmers. And for them, the effect was dramatic. You know, we'd have cases

before the introduction of BT where, you know, farmers were having to treat, you know, it could be 10 times, you know, for these pests. They were going out spraying like 10 times in a season? They could, yeah, some areas. And when the BT was introduced, well, our insecticide sprays just plummeted. And, you know, and there were guys that wouldn't have to treat at all. And that's a big deal for not just the farmers, but for the environment, right? Dan, like, those pesticides don't just kill the insects you're aiming for, right? Yeah, absolutely. Regular insecticides can kill off a whole range of species and mess up the whole ecosystem. B.T. crops produce specific proteins that only kill particular insects. So those

crops are basically harmless to pollinators like bees and beneficial insects that prey on pests and help keep them under control. It's not toxic to people or birds. And for farmers like Jonathan Evans and North Carolina, it meant he didn't have to work so hard. It's always better for the plant to protect itself than for us to have to go out and try to spray for the worms. Did it really change farming? Absolutely. I mean, you can tend a lot more acres with a whole lot less equipment. Got it. So Jonathan the farmer loves these crops.

Julie, who likes insects, is happy. When did things start to go sour, Dan? Well, I guess for Jonathan, it was, you know, one day in 2016 when he went out to his cotton field and saw some cotton bulworms just happily chowing down on his cotton plants. And he knew what that meant. Those insects had evolved. He was looking at a new strain of bullworm that the B.T. protein wouldn't kill. And this has been happening more and more often across the country.

Right. David Kearns, that insect specialist at Texas A&M says some farmers are pretty disappointed and angry. There's words I can't use, but they wanted to know what the heck. They're doing paying for a technology and then they're still having to spray. Okay, Dan, so let's talk about why some of those insects have resistant to BT crops. Yeah. Let's get into the science, Maddie. Evolution. Here we go.

Okay. So there's a part of this that's really simple. You have a gazillion different individual, let's say, cotton bowlworms out there. There's genetic variation among them. And just by chance, you may very well have a few that have some genetic mutation that makes them a little less vulnerable to the BT. Now, they're rare normally, right? No problem. Except if you plant these BT crops everywhere, you kill off all the other insects and you have what biologists call selection pressure.

Right. Those rare individuals that aren't killed by the GMO will be the only ones that survive. And they will find each other. And you know what happens next, Maddie. They do that birds and the bees and the bugs thing. They do. They mate and they have offspring. and suddenly you have a lot of insects with that same genetic trait. A new strain of resistant insects emerged. It's evolution right in front of your eyes.

Wow. That is what has happened over and over. Now, it's complicated because the biotech companies actually deployed a whole series of slightly different BT genes. Got it. And we've seen insects evolve resistance first to one gene, and then the next one. Sometimes it took maybe five years. Other times it took a lot longer, 15, even 20 years. And it's patchy.

You know, like in some places the BT crops are still working and other places they aren't. Okay, but Dan, this idea of selection pressure has been around for a long time, right? So clearly scientists saw this coming. Oh, absolutely they did. In fact, you know, I was around, I was reporting on this back when there were these arguments going on, back when the BT crops were new. And university scientists were predicting that this would happen if the genes were overused. They were pushing this idea of a refuge to keep it from happening.

They said farmers should be required to plant some of their land with non-BT crops. Just so all those pests, you know, those with and without the resistance gene could thrive there. Oh, so in that way, the rare insects with genetic resistance to BT wouldn't completely take over because some of those that were sensitive would still be around to be in the gene pool. Exactly, exactly. And the companies actually agreed to this in principle, but there were these big arguments about how big the refuge had to be. There were some scientists who said, at least for some of these BT crops,

farmers should not be allowed to plant those crops on more than half of their land. But the company said that'll never work. Farmers won't go for BT crops at all if there's such strict rules. and the company's won. And sure enough, now there's resistance to BT. So scientists like Julie are back, you know, once again in this argument, pushing for tighter government rules. We are at an important point where we've seen some examples of what can happen

and definitely do need to make some changes. What kind of changes are we talking about here, Dan? Because it feels pretty late in the game, right? It is, it is. But there's one thing that people are focused on. There's at least one BT gene that is still working, but bugs have not become resistant to it yet. So it still is effective against a lot of insects, and it's sort of carrying a lot of the weight

right now. It's kind of the last BT gene still standing. And scientists are worried it'll soon break, you know, under that weight of overuse, especially in the South, where that gene is used in both corn and cotton to fight off insects. So that the Environmental Protection Agency's scientific advisors have told the agency, it should only allow that gene to be used in one of those crops, cotton or corn. And it should be cotton because controlling the bullworm in cotton is just much, much more important economically. In corn, it's a minor pest. And cotton, it can wipe out your crop. And if you don't let it be used in

corn, then all those cornfields are that refuge. I see. See? But the company that owns this gene, Syngenta says, no, that's not necessary and it's not fair. And the EPA has actually backed away from that idea. Hmm. Okay. I mean, so what happens now, Dan? Well, there are a lot of scientists, including Julie Peterson, who say if current farming practices don't change, it's possible that all of the BT genes that are currently on the market will stop working reliably within 10 years. And then farmers will have to find new ways to fight the insects. Maybe they'll be spraying more insecticides again. Or, and this is what Julie wants, maybe they go back to some more old-fashioned pest control methods.

You know, crop rotations change what crops you plant from year to year. Yeah, I mean, indigenous communities around the world have used that technique for thousands of years. Some organic farmers do too. Right. The trick is going to be using those techniques and still producing the kind of big harvest that a lot of farmers and a lot of consumers now depend on. Okay, Dan Charles, thank you so much for bringing us this story. We appreciate you. It was my pleasure, Maddie.

This episode was produced by Britt Hansen, fact-checked by Ariel Zabidi and edited by Giselle Grayson. Special thanks to Terry Hurley at the University of Minnesota and Dominic Rysig at North Carolina State for their help. I'm Maddie Safaya. Thanks for listening to Shortwave from NPR. Since the 1980s, hip-hop and America's prisons have grown side by side. And we're going to investigate this connection to see how it lifts us up and holds us down. Hip-hop is talking about what we live, trying to live the American dream, felon at the American dream. I'm Sidney Madden.

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