When they retreated from the Battle of Gettysburg, Confederate troops passed by the area that is now Richard Masser’s orchards. If only the latest enemy — the brown marmorated stink bug — would follow suit.
Damage to fruit and vegetable crops from stink bugs in Middle Atlantic states has reached critical levels, according to a government report. That is in addition to the headaches the bugs are giving homeowners who cannot keep them out of their living rooms — especially the people who unwittingly step on them. When stink bugs are crushed or become irritated, they emit a pungent odor that is sometimes described as skunklike.
Suddenly, the bedbug has competition for pest of the year.
Farmers in Maryland, New Jersey, Pennsylvania and other states are battling a pest whose appetite has left dry boreholes in everything from apples and grapes to tomatoes and soybeans. Stink bugs have made their mark on 20 percent of the apple crop at Mr. Masser’s Scenic View Orchards here. Other farmers report far worse damage.
“They’re taking money out of your pocket, just like a thief,” said Mr. Masser, flicking stink bugs off his shirt and baseball cap as he overlooked his 325 acres, a few miles south of the Pennsylvania border. “We need to stop them.”
No one seems to know how. Government and university researchers say they need more time to study the bug, which has been in the United States since about 1998. Native to Asia, it was first found in Allentown, Pa., and has no natural enemies here.
Some people noticed an increase in the stink bug population last year, but all agreed that this year’s swarm was out of control. Researchers say the bugs reproduced at a faster rate this year, but they are unsure why.
“These are the hot spots right now, but they’re spreading everywhere,” Mr. Masser said. “They even found them out in Oregon.”
Populations of the brown marmorated stink bug — different from the green stink bugs that are kept in check by natural predators here — have been found in 15 states, and specimens in 14 other states, according to the United States Department of Agriculture.
The bug travels well, especially as it seeks warm homes before the onset of cold weather.
“It’s an incredible hitchhiker,” said Tracy Leskey, an entomologist with the Agriculture Department’s Appalachian Fruit Research Station in Kearneysville, W.Va. “The adults are moving and looking for places to spend the winter.”
The research station is among three laboratories looking for a solution. Government and university researchers also formed a working group this summer. But Kevin Hackett, national program leader for invasive insects for the Agriculture Department’s research arm, said no immediate solution was in sight.
“We need to do considerable more research to solve the problem,” he said. “We don’t even have a way to monitor the pests. I’m confident that we have excellent researchers. I’m not confident we’re going to find a solution immediately.”
The department is spending $800,000 this fiscal year on stink bug research, double last year’s budget, Mr. Hackett said. But he estimated that seven more full-time researchers were needed, at a cost of about $3.5 million a year for salaries and research expenses.
In Asia, a parasitic wasp helps control stink bug populations by attacking their eggs. Unleashing those wasps here, however, is at least several years away because they would first need to be quarantined and studied.
There has been limited success using black pyramid traps in orchards, Ms. Leskey said. The traps contain scents that trigger sexual arousal. The nymphs, or young bugs, respond seasonlong, Ms. Leskey wrote in a recent report, but adults respond only late in the season, in late August.
Representative Roscoe G. Bartlett, Republican of Maryland, convened a meeting last week of officials from the Agriculture Department and the Environmental Protection Agency. He is pushing to have the stink bug reclassified, which would allow farmers to use stronger pesticides, and is advocating that the Agriculture Department reallocate $3 million of its budget for research.
A problem that can arise when more pesticides are used, experts and farmers say, is that many years’ worth of effective “integrated pest management” can be ruined in the process. Farmers kill some pests but allow others to live because they prey on yet other pests. Wasps, for example, eat worms that otherwise would kill crops.
“It is a way to use nature’s own defenses against pests in orchards,” said Steve Jacobs, an urban entomologist at Pennsylvania State University. “That’s been finely tuned and works well. This brown marmorated stink bug blows all that out the window. You kill them today, new ones come tomorrow. So this is a serious problem.”
Meanwhile, homeowners in the region are coping with this latest nuisance.
Vicky Angell of Thurmont, Md., said she first noticed the stink bugs last year, but “not in flocks” like this summer. She kills about six a day and suspects that they get inside her home when she leaves the door open to let the dog out.
Ms. Angell said she flushes them down the toilet after catching them in a napkin. Other people use their vacuum. And many have turned to exterminators.
Stink bugs, whose backs resemble knights’ shields, do not bite humans and pose no known health hazards — even the fruit they have gotten to is edible, once the hardened parts are cut out. They leave small craters on the surface of an apple or pear, and the inside can get brown and corklike. Females can grow to nearly the size of a quarter. “Marmorated” refers to their marbled or streaked appearance.
Still, sometimes they are just too close for comfort. Ms. Angell said she got a surprise when she put on her pants Friday morning, having washed them and left them to dry in her laundry room.
She felt something in the right rear pocket.
“I thought I left a piece of paper in them when I washed them,” she said.
But it was not paper.
“Pulled it out. He was alive. Stink bug. Flushed him down the toilet,” she said. “I thought, I’m glad I didn’t sit on that.”
Kelli Wilson of Burkittsville, Md., said her home had been overrun by the bugs, especially in the past week. In the afternoon sun, the north-facing exterior of the house “is black with stink bugs,” she said. “It looks like the wall is crawling.”
Mrs. Wilson’s husband, Raymond, skipped services on Sunday at St. Paul Lutheran Church in Burkittsville to remove stink bugs from the house. Mrs. Wilson discovered a little hitchhiker as she and her children arrived at the church. “I just pulled into the parking lot and there’s one on my purse,” she said. “They travel with me now.”
Mr. Jacobs, the urban entomologist, said the response to stink bugs so far is not an overreaction. “I’m standing here in my living room watching some of them crawl up my walls,” he said. “The best thing to do is make your house as tight as possible. Use masking tape to seal around sliding glass doors, air-conditioners.”
Mr. Masser, the Sabillasville farmer, said that he had not yet raised his prices to offset losses, but added that it was a possibility next year if a solution to the stink bug invasion was not found.
“Stink bugs are going to destroy a lot of food — it’s just starting,” he said. “When Joe Blow starts hollering because he can’t find the food he wants, they’ll respond then.”