Parastic Wasp Could Fight Lanternfly Invasion : Short Wave The spotted lanternfly is eating its way through trees and crops in eastern Pennsylvania. NPR science correspondent Dan Charles explains how scientists hope to stop the spread of this invasive pest by importing a natural enemy from its home in China. Follow host Maddie Sofia on Twitter @maddie_sofia. Email the show at

Fighting An Insect Invasion With... An Insect Invasion

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You're listening to SHORT WAVE from NPR.

Maddie Sofia here with NPR science correspondent Dan Charles.

Hi, Dan.


SOFIA: So today you brought us a story about a bug.

CHARLES: A bug...


CHARLES: ...That was native to China. It's called the spotted lanternfly. Problem is, it's not just in China anymore. In fact, right now it is eating its way across eastern Pennsylvania.


UNIDENTIFIED REPORTER #1: An invasive fly has shown up in our region. It's called the spotted lanternfly.

UNIDENTIFIED REPORTER #2: Spotted lanternfly...

UNIDENTIFIED REPORTER #3: Adult spotted lanternfly...

UNIDENTIFIED REPORTER #4: State officials say it's capable of destroying trees and crops, potentially costing millions in damage...

CHARLES: There are whole Facebook groups where people trade stories about how to kill them. Recently, the Philadelphia police had to tell people, please do not call 911 to report these bugs.

SOFIA: Yeah.

CHARLES: Basically, the state is saying if you see a bug, just smash it. Right? Just, like, kill the spotted lanternflies...

SOFIA: License to kill.

CHARLES: Yeah, yeah.

SOFIA: So this is, like, obviously a huge problem.

CHARLES: It is. It has no natural enemies here, at least not enough of them to really sort of hold it in check. So it is ready to spread across the country. And scientists are considering something that sounds a little weird at first. They're talking about importing this bug's natural enemies from back in China - an invader to fight an invader.

SOFIA: This episode, the spotted lanternfly; how they got here and what scientists are trying to do about it.


SOFIA: So, Dan, the spotted lanternfly - you went to Pennsylvania to check these guys out.

CHARLES: Yeah, to Allentown. I went to a park. I was walking around. And I did not even notice the spotted lanternflies at first. And then Heather Leach showed up.

HEATHER LEACH: Nice to meet you.

CHARLES: Hey. Nice to meet you.

LEACH: Figured it was you (laughter).


She's an insect expert at Penn State University. And Heather takes me over to these trees and starts pointing things out.

LEACH: They're kind of underneath the ivy here. But if you kind of peek under these leaves, you'll start to see just large...

CHARLES: Oh, sure enough, they're climbing up underneath the ivy.

LEACH: Yeah.

CHARLES: And that is when I realized they were actually all over that tree, all the way up to the top...

SOFIA: Once you saw them, you couldn't unsee them.

CHARLES: Over the branches - they were sucking sap from the tree.

To every - most people kind of know what they are at this point.

LEACH: Oh, yeah. Most people are sick of them in this area. They try to kill them as much as they can...

CHARLES: Heather pointed out this other thing that I really wouldn't have noticed. We were standing under this tree. And I could feel little drops of moisture, like the pitter patter of a light rain. And Heather told me this was actually coming from the bugs. They excrete drops of sugary water called honeydew, so what I was feeling was actually bug poop.

SOFIA: (Laughter).

LEACH: It's pretty gross. And what we're seeing is that people who have this, you know, lanternfly in their backyard are literally - they're getting pooped on when they're sitting outside on their patio. Or their car is getting pooped on. And then you start to get mold growth on that. And it gets very gross (laughter).

SOFIA: OK. I mean, honeydew sugar poop doesn't sound like the worst poop in the world, but I get it.

CHARLES: Right. Right.

SOFIA: If there's, like, a mold aspect to it afterwards, that's concerning.


SOFIA: OK. So when did they show up? - because I haven't even heard of this.

CHARLES: They got here five years ago. The first couple of years, there weren't many. They were just here and there. And people were thinking, well, maybe they actually aren't going to invade that much. But the last few years, I mean - (laughter). There are billions of these insects probably. And the spotted lanternfly - despite its name, it doesn't really fly, but it can really jump. And it goes in hordes. It swarms on trees, on houses, on porches. Nobody knows exactly how they got here. Chances are some lanternfly eggs hitched a ride on a shipping container across the Pacific. They don't have any natural enemies. And at the same time, they've got a lot of food out there...

SOFIA: Right.

CHARLES: ...Tons of trees with sap that they like to drink.

LEACH: They've got a buffet out here. They can eat all of these plants. And they don't have anything that's taking them down, so they're having a good time. They're having a party, right?


SOFIA: So - OK. They're obviously problematic. They're not harmful to humans in any way.

CHARLES: No. They're not going to bite. They're not going to sting. But at the same time, you know, these insects are not a joke.

SOFIA: Right.

CHARLES: You know, they really can destroy things. And the people who are seeing this first, who are really getting hit, are the vineyard owners in that part of Pennsylvania, where we met a guy named John Landis at Vynecrest Winery.

LEACH: Morning, John.

JOHN LANDIS: Hey. Good morning.

LEACH: (Laughter).

CHARLES: He's a smiling guy, cheerful. But then I asked him about the lanternflies, and he got pretty serious.

LANDIS: We've never had a situation like this in 40 years. If it starts to decimate your vineyard, it could cause people to go out of the winery business. And Heather can go out, and she'll show you some examples of that.

CHARLES: So that's exactly what we did. We walked out into the vineyard. And sure enough, you know, the rows of vines next to the woods, especially - first of all, they were full of lanternflies. And a lot of the vines were already dead from last year's attack.

LEACH: Yeah. And you'll also notice that what's not dead here isn't producing any grapes. And so we think it's a product of winter injury because as a product of lanternfly depleting those resources, they don't have enough to survive the winter. And so...

SOFIA: So she's saying that the lanternflies kind of, like, suck up all the sap and nutrients out of the plants. And so even if they survive, they can't make fruit.

CHARLES: Right. Now, you know, I should say, the vineyard owners, they can protect themselves, right? They can spray insecticides. But if you start doing that, first of all, it costs you money.

SOFIA: Sure.

CHARLES: And second, it doesn't help with the really big problem, which is the ecosystem problem.

LEACH: So we're worried about forest regeneration and native plants. We're also starting to see early indications of displacement of other insects and, as a result, displacement of birds as well.

SOFIA: I feel like this is the story of, like, every invasive species, where we can't really anticipate how severe, like, the ecological consequences are because all these species are kind of dependent on each other.

CHARLES: Yeah. And you often can't predict, like...

SOFIA: Right.

CHARLES: ...How the different pieces interact. And, you know, sort of - it's like this giant puzzle. It's really complicated. So as, you know, she was telling me this, I was feeling like, this is basically hopeless, right? (Laughter).

SOFIA: Yeah. Yeah.

CHARLES: You know...

SOFIA: It doesn't look good, for sure.

CHARLES: The lanternfly is here to stay. And who knows what'll happen?

SOFIA: Right.

CHARLES: But then she told me about this idea. She was saying there are scientists who say, look. If the problem arrived here from China, maybe we could bring the solution from there, too.

SOFIA: Yeah, maybe...

CHARLES: (Laughter) You see...

SOFIA: ...Dan, maybe.

CHARLES: You see, back in China, the lanternfly has these natural enemies that hold it in check. They're tiny little wasps, so small you can barely see them.

SOFIA: I don't like that. Keep going.

CHARLES: They don't sting you.


CHARLES: But two of these wasps - there are different kinds of them. And they've coevolved with the spotted lanternfly so that their life cycle is kind of intertwined with the spotted lanternfly. So one of them, for instance, lays its eggs inside the spotted lanternfly eggs...


CHARLES: ...So that when the wasp egg hatches, it feeds on the spotted lanternfly egg.

SOFIA: Interesting.

CHARLES: Another wasp lays its eggs inside the nymph stage of the spotted lanternfly, when it's kind of like a baby spotted lanternfly. And again, the egg hatches. And the larva eats the nymph and then emerges and spins a cocoon until it emerges as a...

SOFIA: (Laughter).

CHARLES: ...You know, a full-blown wasp again, ready to, like, attack another spotted lanternfly.

SOFIA: Unsettling and effective.

CHARLES: So some scientists from the U.S. Department of Agriculture have actually gone to China. And they have collected these natural enemies of the spotted lanternfly. And they now exist in quarantine...

SOFIA: (Laughter) What?

CHARLES: ...In these labs in a couple of different places here in the U.S.

SOFIA: So are they hoping to set this parasitic wasp free soon? Or is this in the very distant future?

CHARLES: Well, this is at least a few years in the future because they have to do all these tests. They can't release these wasps without approval from federal regulators. And the regulators are going to be looking at things like, do we know that it only attacks...

SOFIA: Right.

CHARLES: ...The spotted lanternfly and not a bunch of native - you know, other native species? So they have to do a bunch of experiments. And honestly, it's not clear how long it'll take for them to make their case to the regulators that this is safe to release.

SOFIA: How big of a problem is this? Like, give me an estimate of the scale.

CHARLES: So this is a really hard question to answer because, you know, it was kind of interesting walking around with Heather Leach. We're talking about, like, a big ecosystem problem. And at the same time, we're kind of laughing about it. The thing is we have kind of seen this movie before, right? This is not the first big invasive insect that's landed here, probably won't be the last. You know, we can think of some of the other ones that have, you know, wreaked havoc on ecosystems.

SOFIA: Sure.

CHARLES: There was the gypsy moth, if you remember that, you know - another recent one, the brown marmorated stink bug, the one you've discovered in your mattresses.

SOFIA: I hate that bug so much.

CHARLES: Yeah, so these things have sort of washed through. And some of them are more destructive than others. How the spotted lanternfly will stack up in the end - you know, it'll be interesting to see.


SOFIA: NPR's Dan Charles.

Thank you, Dan.

CHARLES: Thank you.

SOFIA: If you're listening to this and there is an invasive species that's a huge deal where you live, we want to hear about it. Email us at -

Thanks for listening. I'm Maddie Sofia. And we're back with more SHORT WAVE from NPR tomorrow.


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