An insect with a voracious appetite, no domestic natural predators and a taste for everything from apples to lima beans has caused millions of dollars in crop damage and may just be getting started.
The brown marmorated stink bug, a three-quarter-inch invader native to Asia, is believed to have been brought first to the Allentown, Pa., area in 1998. The bug began appearing in mid-Atlantic orchards in 2003-04 and exploded in number last year.
This spring, stink bugs have been seen in 33 states, including every one east of the Mississippi River and as far west as California, Oregon and Washington.
"All that we do know for certain is that a tremendously large population went into overwintering in fall 2010. So, if they survived, there could be a very large population emerging in the spring," said Tracy Leskey, a research entomologist at the U.S. Agriculture Department's Appalachian Fruit Research Station in Kearneysville W.Va.
Growers in the mid-Atlantic region have reported the worst problems, and the apple industry appears hit hardest, with $37 million in damage to growers in Maryland, Pennsylvania, Virginia and West Virginia, according to the U.S. Apple Association. That's about 18 percent of the Mid-Atlantic crop.
Mark Seetin, the association's director of regulatory and industry affairs, called it the worst threat to farmers he's see in his 40 years in agriculture.
Growers in Washington state, the nation's biggest apple producer, haven't seen major damage so far, said Mike Willett, vice president for scientific affairs for the Yakima, Wash.-based Northwest Horticultural Council. The bug was first spotted in the state a couple years ago.
The bug, named for the foul smell it gives off when crushed, will feed on nearly anything, including cherries, tomatoes, grapes, lima beans, soybeans, green peppers, apples and peaches. It uses a needle-like mouth to pierce the skin of its host fruit or vegetable, leaving behind a spot that is disfigured and discolored.
Stink bugs wiped out up to 40 percent of Tom Haas' peaches last season at his Cherry Hill Orchards in Lancaster, Pa. The peaches looked so bad that Haas let the fruit fall to the ground, where it rotted.
"This is the worst, probably, that I've dealt with in 25 years," said Haas, the owner of the family-run orchard. "The damage they do to fruit is horrendous."
Damaged fruit is safe to eat, but the blemishes drastically reduce prices. Growers, for example, get about $3 a bushel for apples sold cider, compared with $30 per bushel for the best, pick-your-own apples.
At Catoctin Mountain Orchard, about 10 miles south of the Maryland-Pennsylvania line, owner Robert Black said he didn't realize how bad the stink bug damage was until his apples ripened.
"My late varieties of Pink Ladies is what really took the damage," Black said. "We had a 50 percent damage there."
Federal researchers have set up devices in Black's operation and in eight other commercial orchards in Maryland and West Virginia to monitor the bugs.
Other scientists from North Carolina to New York are scrambling to fight back against the pests.
U.S. Rep. Roscoe Bartlett, R-Md., began demanding federal action last year after hearing from orchard growers in his western Maryland district.
"If I was a mad scientist doing gene splicing and putting together a bug that would really be nasty and I was turning it loose on my enemy, I probably couldn't do a better job," Bartlett said. "One might define this thing as the bug from hell."
Researchers are considering long-term solutions, such as finding chemicals that can attract stink bugs to traps before they can feed on fruit -- a strategy that has worked in controlling Japanese beetles. Some also are researching the importation of the stink bug's main Asian predator, the parasitic wasp, though that work could take years to ensure the wasps wouldn't cause their own set of problems.
For growers seeking immediate help, the best hope is an insecticide called dinotefuran, the active ingredient in the commercial products Venom and Scorpion. The chemical compound is labeled by the Environmental Protection Agency for use on vegetables, grapes and cotton, but not in orchards, as it is in Japan and other Asian countries.
The EPA said manufacturer Mitsui Chemicals didn't seek to have dinotefuran licensed for tree fruit applications when the agency approved the insecticide in 2004. Now the EPA is reviewing an emergency-exemption petition from the Virginia Department of Agriculture and Consumer Services that could allow the compound's use in orchards in Delaware, Maryland, New Jersey, North Carolina, Pennsylvania, Virginia and West Virginia starting in mid-July.
At a recent meeting with growers at a Penn State research station in Biglerville, Pa., tree-fruit entomologist Greg Krawczyk warned that insecticides couldn't provide an easy solution.
"When you spray the crop with completely legal, viable insecticide, you will kill the stink bug, but the problem is that you will do it today, and a few days later you will have another whole group of them migrating from the outside," Krawczyk said. "So they just keep moving."