By Olesia Plokhii

MediaNews

A little brown bug emitting a pungent, apple-like odor that has earned it the name of "stink bug" is being sighted in high numbers in the region this fall, with desperate homeowners calling exterminators to rid their houses of the pesky critters.

Although the bugs don't bite or chew through clothes or wood, they have become a nuisance for locals who are finding them clustered by the dozen on window sills, door frames and home siding, where they hibernate for the winter.

"We noticed them a couple weeks ago when I opened my daughter's shades and she said, 'Ewwww, gross,'" Joseph Simao, of Townsend, said last week about the bugs in and around his home. "I haven't seen them in the numbers I'm seeing them now."

Phyllis Donahue, of Security Pest Elimination, a Lowell-based extermination company, said she gets half a dozen calls a day from homeowners looking for help getting rid of the "stink bugs" -- an "invasion" when compared to recent years.

But despite the headache these bugs have brought,many homeowners don't realize they are dealing with an imposter. The stinky bug congregating around crevices in their homes is not technically a stink bug -- it's a look-a-like bug called a western conifer seed bug. Although the conifer bugs are little more than an annoyance, the real "stink bug" is wreaking real havoc elsewhere -- and could be heading to the area soon.

First spotted in Pennsylvania in 2001, the invasive brown marmorated stink bugs have since spread to 38 states, and are among the most damaging agricultural pests in the country. The feeding process of the bugs, which sees them suck juice from fruit, simultaneously rots the fruit, making it impossible to sell, said Dr Tracy Leskey, a stink-bug expert with the United States Department of Agriculture.

Leskey, who is working to combat the spread of the bug around the country, said that 2010 proved to be the most destructive year for apple crops bitten by the bug, with $37 million in losses for the apple industry in the mid-Atlantic region. Although higher numbers of the bug have been spotted in states like West Virginia, Virginia and Maryland this year, Leskey said a lack of data makes it hard to forecast national trends, but that Massachusetts has had low detection levels over the years.

"But this bug is tough, highly mobile, moves in an out of crops and is hard to kill," Leskey said, adding the "hitchhiker" bug travels from state to state by latching on to cars.

UMass Amherst fruit-tree specialist Jon Clements, who was part of a team that set up a trap for the stink bug at Parlee Farms in Tyngsboro, said that while the bug hasn't made its way to the area yet, farmers should be on the lookout.

"Most people think it is a matter of time before they get here in quantity," Clements said. "We're hoping that before they get here in high numbers, they will release the wasp."

Clements is speaking of any ordinary wasp, but a killer, parasitic wasp that USDA scientists are hoping will act as a natural predator against the stink bug. They are studying two groups of wasps, Asian and American, to determine which one will be deadly.

"We are studying (the two groups of wasps) so we can tell them apart to determine if the native species will be effective or we'll have to import from Asia," said Matthew Buffington, a USDA entomologist, last week from Washington, D.C., about importing wasps from China, the stink bug's country of origin. His colleagues are testing a batch of Asian wasps in a quarantine lab, he said, and could be ready to choose the killer wasp in two years.

But while the area waits for the real stink bug to make its debut, residents aren't taking much notice of the difference.

"Everybody calls them the stink bugs around here," said Teresa Elder, 23, of Billerica. "We kill about six or seven a night -- it's definitely annoying."