Stink Bugs May Reunite With Old Nemesis

By now it almost seems like everyone in the D.C. region has first-hand experience with the brown marmorated stink bug.

"It was black -- all my walls. There were so many last year," says Fabi Moradian.

The shield-shaped insects were introduced from Asia and descended on the region with the fury of a plague last year. If you bother or crush them, the bugs smell like cilantro and burning rubber. But for Bob Black, they're more than just a nuisance.

"This thing is really gonna put a big chapter in my book of life. I've never had anything affect me like this," he says.

Black runs Catoctin Mountain Orchards in Thurmont, Md., where his family grows everything, including plums, tomatoes and pears.

The apricot blossoms are just starting to come out, and Black is starting to worry. Just like many other farmers across the region, Black saw his crops decimated by marmorated stink bugs. With their long, needle-like mouthpieces, the insects pierce the flesh of fruits and vegetables and leave them bruised and disfigured.

"One of our late varieties -- Pink Lady, which a lot of people like, that's the latest apple -- we had up to 50 percent damage on that. I can handle a few percent, but if it gets up to 25 percent, 50 percent that's pretty devastating to me," he says.

And as Black discovered, his usual pesticides didn’t really do much.

"This one can actually play in it and eat it and it won't even kill it that's how tough this insect is," he says.

And this year will probably be worse.

"We're gonna hear a collective wail up and down the East Coast and in the metro area as hordes of these things come out of people's attics and find their way outdoors," says Mike Raup, an entomologist at the University of Maryland.

He says the population has grown exponentially, and he says the bugs are moving out from the epicenter of Allentown, Pa.

"They're now found in more than 30 states, as far west as Washington and California, as far south as Florida, they've been detected. But right here in the mid-Atlantic region this is ground zero for the brown marmorated stink bug," he says.

When you boil it all down, the basic problem is simple he says.

"They simply arrived here without their full complement of natural enemies," Raup says.

A hundred miles away in Newark, Del., that is exactly what the U.S. Department of Agriculture is working on. Outside a red door marked "Quarantine," entomologists Kim Hoelmer and Kathy Tatman are suiting up.

"If there were an insect loose in Quarantine...it would stay on the outside of our quarantine suit, rather than getting into our hair or getting into our pockets," Hoelmer says.

Behind this door are a myriad of foreign insects being evaluated to see if they can fight invasive foreign pests that have gone wild in North America.

After passing through a number of chambers, the entomologists reach a series of dark, glowing red corridors.

"All the light is red. To minimize insect flight movement. Because most insects can't see red this looks like a dark room to them," Hoelmer says.

Everything is designed to prevent escape.

"All the air and the water coming into and out of quarantine is filtered...which will keep anything larger than a virus from passing through," he says.

Tatman pulls out tray after tray of little vials and petri dishes from modules whose temperature, light, and humidity are precisely controlled.

Inside the little vials, rafts of tiny pearly green orbs sit on leaves. They're stink bug eggs. And there's something else: Tiny black dots are zipping around in the jars. Parasitoid trissolcus wasps from China, Japan and Korea. Just 2 millimeters long, they don't look like much more than gnats. They don't bite or sting, and they feed on nectar, but in Asia, they are the natural nemesis of the Brown Marmorated Stink Bug.

"These small wasps will deposit their eggs inside the stinkbug eggs. Then the parasite egg hatches, and the immature feeds on the inside of the stink bug egg," Hoelmer says.

In a few weeks, out pops a new wasp, and no stink bug. He says these wasps are extremely specialized evolutionarily.

"If they can't find stink bugs or stink bug eggs to lay their own eggs in, they'll die. They can't survive on anything else," he says.

But there are almost 300 types of stink bugs in the United States and a lot of them are helpful because they eat other pests. So Hoelmer needs to know: Would these wasps ever go after other stink bugs? What about stink bugs that are really, really closely related to the brown marmorated stink bugs? What if they were locked in a jar with no other option? Well, Hoelmer will test exactly that, putting the wasps with different stink bug species to see what happens.

"If we've chosen wisely, we have a good image of the specificity of the wasps. If they won't attack any of the close relatives, they won't be as likely o attack more distant ones," he says.

It'll take three years before he's satisfied that the wasps don't pose a risk. Hoelmer points to examples where this has worked before –- Gypsy Moths were controlled by an introduced fungus, white flies in California were cut down by other parasitic wasps.

Back at Catoctin Mountain Orchard, Black can't wait.

"Using the wasp will hopefully be our answer, I mean we've had other things -– drought, other issues -– but this insect is one of the toughest things that we're gonna have to work on," he says.

Until then, seven states are asking the EPA to relax pesticide regulations, researchers are looking at pheromones, traps, and naturally repellant landscape plants –- none of which are considered fully effective.

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