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A bug recently arrived from China is munching its way across eastern Pennsylvania. From there, it's poised to spread across much of the country, killing trees and grapevines. So scientists are considering something drastic - importing other insects, the bug's natural enemies from the place it came from. NPR's Dan Charles has the story.
DAN CHARLES, BYLINE: I was walking around a park near Allentown, Pa., and I didn't even notice the bugs at first. Then Heather Leach arrived, the insect expert from Penn State.
HEATHER LEACH: But if you peek under these leaves...
CHARLES: Oh, sure enough, they're climbing up underneath the ivy.
And then I realize they're all over this tree - spotted lanternflies, a marching column of grey bugs, each one about an inch long, black spots on their wings, sucking sap from the tree.
LEACH: They are kind of ugly, especially when there's thousands of them. You'll start to poke at them, and you'll see how strong of a hopper they are. You see that? They just take off.
LEACH: Yeah, they can be entertaining. You see a lot of kids running around, playing with them, trying to stomp on them.
CHARLES: Spotted lanternflies first showed up in the United States five years ago right here in Berks County. Nobody knows exactly how. Some eggs probably hitched a ride on shipping containers across the Pacific. Now there are hordes of them spreading across Pennsylvania and beyond. Chances are they'll eventually reach most of the country.
LEACH: It's an insect that lays its eggs on anything - including things that get transported - hops onto vehicles and can hold on.
CHARLES: They don't seem to have any natural enemies here, but they've found lots of trees with sap that they like.
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?
CHARLES: Heather Leach gets panicked calls from people with swarms of lanternflies on their houses or their trees. She tells them, don't freak out. These bugs won't bite or sting, but they're not a joke, either. They really can destroy things, and the people who are seeing this first are vineyard owners like John Landis at Vynecrest Winery west of Allentown.
LEACH: Morning, John.
JOHN LANDIS: Hey. Good morning.
LEACH: How are things going?
CHARLES: Landis is pressing grapes, smiling. Harvest is a good time, he says. But then I ask him about the lanternflies, and he turns serious.
LANDIS: We've never had a situation like this in 40 years. If it starts to decimate your vineyard, it can cause people to go out of the winery business.
CHARLES: It's actually killed vines?
LANDIS: Oh, yeah, definitely. It kills vines.
CHARLES: We walk out into the vineyard, and sure enough, the section next to the woods is infested with lanternflies. A lot of vines are dead already from last year's attack.
LEACH: We had lanternfly just kind of pouring out of these trees last year and invading this area here and then down on this hill.
CHARLES: Vineyard owners can spray insecticides and protect their crop, but that's costly, and it can kill helpful insects like bees and ladybugs. Also, it doesn't help with the bigger problem - the damage lanternflies can cause to whole ecosystems. Leach says scientists are worried they might kill off some trees and forests.
LEACH: We're also starting to see early indications of displacement of other insects and, as a result, displacement of birds as well.
CHARLES: But maybe, she says, if the problem came from China, the solution could, too. You see, back in China, the lanternfly has natural enemies that hold it in check - tiny wasps so small you can barely see them. Scientists from the U.S. Department of Agriculture have brought two kinds of these wasps to the United States. They're under quarantine in a couple of USDA labs like the Beneficial Insect Introduction Lab in Newark, Del. Two USDA scientists, Amanda Stout and Kim Hoelmer, lead the way into the quarantine room. We're all suited up in white overalls head to toe.
AMANDA STOUT: That next door is high-security.
KIM HOELMER: This quarantine zone is filled with these environmental chambers.
CHARLES: They look like big refrigerators. Hoelmer opens one up and points me towards something in a sealed container.
HOELMER: There's a little white thing about a quarter of an inch long with a dark...
CHARLES: Yeah, I see it.
HOELMER: ...Spot in there.
CHARLES: I see it.
HOELMER: That is the cocoon.
CHARLES: This is one stage in the life cycle of a lanternfly-killing wasp. The wasp lays its eggs inside baby spotted lanternflies, called nymphs. The eggs hatch into larvae that feed on the nymphs and kill them. So maybe they could do this outside the lab in Pennsylvania's forests. Sounds kind of crazy - releasing an invader to fight another invader - but Hoelmer says, really, it could work.
HOELMER: There are many, many examples of successful and safe introduction of natural enemies.
CHARLES: He says it's best when the natural enemy's a specialist - when it only attacks the invasive species you're trying to control - so now he's trying to figure out whether these wasps only lay their eggs in lanternflies or if they attack North America's native insects, too. Getting answers will take years. In the meantime, the lanternflies will keep on moving.
Dan Charles, NPR News.
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