Mid-Atlantic invaded by stink bugs

WASHINGTON — Shaped like shields and armed with an odor, dime-size brown bugs are crawling into homes over windowsills, through door crevices and between attic vents in such numbers that Washington, D.C.-area homeowners talk about drowning them in jars of soapy water, suffocating them in plastic bags or burning them with propane torches. In the process, some people are unwittingly creating another problem: When squashed or irritated, the bugs release the distinctive smell of sweaty feet.

Get used to it, experts say: The invasion is going to get worse.

"This is the vanguard," said Mike Raupp, a University of Maryland entomologist and extension specialist. "I think this is going to be biblical this year," he said. "You're going to hear a collective wail in the Washington area ... like you've never heard before. The [bug] populations are just through the ceiling."

The change in season, as days shorten and night temperatures dip, is nature's call to the brown marmorated stink bug to leave its summer gorging grounds and seek refuge inside. What's happening is a massive population shift from orchards, cornfields and gardens, to suburban homes, office buildings, hotels, the urban U.S. equivalents of rocky outcroppings in the stink bug's native Asia.

Stink bugs are harmless to people and their possessions. They don't bite. They don't sting. They're not known to transmit disease. But their population has grown so tremendously that they are vexing homeowners and, for the first time, damaging fruit and vegetable crops, from peaches and apples to soybeans and corn and ornamental shrubs and trees.

There is no easy way to kill lots of the bugs at once. They have no natural predators in the United States; existing pesticides don't work effectively. They travel easily — hitching rides on vehicles, in packing materials, on concrete blocks — and adapt to winter in homes. As a result, they have flourished, spreading to 29 states since they arrived in Allentown, Pa., in 2001, likely stowaways in a shipping container from Asia. They are native to Japan, Korea and China, where they are known as "stinky big sisters."

And now they are causing a stink in the mid-Atlantic region.

Keeping them out

Experts say homeowners should prevent the pests from coming indoors by sealing cracks with caulk and using weatherstripping around doors and windows. If the bugs do get inside, residents can vacuum them up, remove the bag and put it in the garbage. The danger, though, is that squashed stink bugs can smell up the vacuum cleaner.

Experts warn against using pesticides not intended for residential applications because that can cause illness and make homes unsafe — and might not solve the problem.

In Loudoun County, Va., longtime Middleburg resident Margo Tate uses the squish-and-toss method. Or rather, her husband does. "I'm looking out my window here and I bet I have 30 of 'em on the screen," she said. "I have to keep all the windows and doors closed. My husband smushes them and throws them in the trash. They're a mess. They smell when you squish them."

Stink bugs are nowhere near the menace of bedbugs, which feed on human blood and whose alarming resurgence prompted the U.S. Centers for Disease Control and Prevention to issue an unusual statement about their public-health impact.

Homeowners may have been caught by surprise by the stink bugs, but farmers have reason for real distress.

A news release, issued to homeowners and gardeners by Maryland's agriculture department, warned about the growing menace. Backyard gardeners are noticing stink bugs eating through their tomatoes, peppers and raspberries. The bug is "emerging as a devastating pest to orchardists and potentially to soybean growers," officials said.

"In Maryland this year we have had the most extensive brown marmorated stink bug damage to both tree fruit and vegetables ever reported in the U.S.," said Jerry Brust, a University of Maryland pest expert.

Bob Black, whose 100-acre Catoctin Mountain Orchard in Thurmont, Md., has peaches, apples and other fruits and vegetables, said he has lost about 20 percent of his crop to the pest. Initially growers were calling one another and attributing the damage to a freak cold in the spring. He said he thought to himself, "Gee whiz, this is freeze damage I've never seen before. I prayed it was, but this stink bug is really the problem."

U.S. Rep. Roscoe Bartlett, a Republican who represents Maryland's rural 6th District, has with other members of Congress asked Agriculture Secretary Tom Vilsack and Environmental Protection Agency Administrator Lisa Jackson to come up with a strategy to deal with halyomorpha halys.

"He doesn't like to call it a stink bug," said aide Sallie Taylor. "It doesn't sound as serious as it should be."

Because so little is known about the insect, researchers at the U.S. Department of Agriculture (USDA) and state universities in Maryland, Pennsylvania, Delaware, Virginia and New Hampshire (the bug popped up there for the first time this year) have formed a Brown Marmorated Stink Bug Working Group. Among the group's priorities are studying the bug's basic behavior and biology, identifying natural ways to control it and developing a public-awareness campaign.

Scientists don't know, for example, whether last winter's heavy snows gave the bugs extra insulation from the cold, or whether the summer's heat and drought created ideal conditions for its reproduction.

Tracy Leskey, the USDA scientist and a leader of the working group, made the first positive identification of a specimen in Maryland in 2003. She's been tracking them since from her research station in Kearneysville, W.Va. In her home outside Shepherdstown, thousands of bugs are now in her attic, she said. Other residents reported thousands massing on the sides of their homes.

"I have never seen anything like this in my career," said Leskey, 42.

Researchers are racing against the clock to find ways to kill the stink bugs.

At a USDA lab in Newark, Del., scientists have quarantined tiny parasitic wasps, collected from China and Korea, where they are the bugs' natural predators, to determine whether the wasps can be used against the stink bugs without harming other species here. The wasps attack the eggs of the stink bugs. Researchers estimate that they will need two more years before they can introduce a natural enemy.