Saturday, September 29, 2007

Bugs cause big stink in the Big Lick

Entomologists say Roanoke and Lynchburg seem to be hotbeds of stink bugs.

Truck on fire

Kyle Green | The Roanoke Times

Adult stink bugs are about six-tenths of an inch long, generally a dark, mottled brown in color and equipped with characteristic white and dark banded antennal segments.

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Stink bugs in Hitchcockian numbers buzz the region these days as autumnal annoyances. They cling to window screens and walls. They mightily enjoy piercing apples with their tiny beaks and their small, sucking mouth parts.

An insect expert at Virginia Tech said Thursday that the Roanoke Valley seems to be Virginia's hotbed for the brown marmorated stink bug -- an exotic, invasive species that apparently hitched a ride to the Northeast more than a decade ago via Asian imports. It has been moving south ever since.

"Roanoke, I believe, has got the hottest, the largest densities of these things [in Virginia]," said Tom Kuhar, a professor of entomology at Virginia Tech.

He and other entomologists aren't sure why the bugs like Roanoke. (Of course, people always say Roanoke is a good place to raise a family.)

In fact, the very first brown marmorated stink bug Kuhar encountered was the one he recently observed hanging with homeys on an exterior wall of a Roanoke Valley hotel.

But wait.

Entomologist Eric Smith, director of technical services for Lynchburg-based Dodson Brothers Exterminating, said the Hill City is a brown marmorated hotspot too. He said Dodson Brothers in Lynchburg has received more stink bug related calls this year than ever before.

For homeowners, the bugs are like in-laws -- pesky visitors reluctant to leave. They don't bite. They don't sting. They seem a bit dim-witted, even for bugs, but are skilled at flying.

"That's how they are traveling south so fast," moving from Allentown, Pa., where the exotic species was first identified, he said.

For fruit growers, they're pests.

"The brown marmorated stink bug could be a big threat to the fruit industry," said Kuhar. "They basically feed on fruit."

Other stink bugs savor fruit too, he said, but the Asian model presents a greater threat, "because it aggregates in such large numbers."

At Ikenberry Orchards in Botetourt County, Ben Ikenberry said he's seen both brown and gray stink bugs this fall but not in noticeably higher numbers. Ikenberry had not heard about the brown marmorated variety, but he said stink bugs can damage apple crops cosmetically.

"They can put a sting injury on the apple that leaves a little blemish," he said.

The orchard controls stink bugs, aphids, moths and other apple pests with Asana, a use-restricted insecticide, he said.

Becky Price at Cline's Farm in Clear Brook, near Winchester, said they've spotted some brown marmorated stink bugs in the farm's orchards. Like Ikenberry, she said Cline's Farm battles this species as it does other stink bugs -- through spraying.

Now, as cold weather approaches, the marmorated stinkers prepare to mass in clusters. Why do they cuddle up come winter?

Probably to stay warm, said Kuhar. Mate finding is another motivation to mingle, said Ames Herbert, a colleague of Kuhar's at Virginia Tech.

Like Alfred Hitchcock's gulls and crows, the bugs are gathering now. Soon, they'll congregate more intimately, often becoming snug squatters in attics and walls.

If that fact alone isn't sufficiently shudder-inducing, the bugs also, of course, stink. Stink bugs are the skunks of the insect world (though other bugs smell bad too). When threatened, they emit a pungent, fairly sweet odor from glands in the thorax. The stink seems to discourage some potential predators, like birds. But Kuhar said it also warns fellow stink bugs "that there's trouble brewing and they better go hide."

But what can homeowners do?

Vacuum up or collect the bugs by hand, said Kuhar. First, though, consider this: Smith said Dodson Brothers has been advising callers to avoid using the household's best vacuum because the bugs' death throes' stink can linger for a very long time.

"Probably the best thing to do right now is go out and buy a cheap Shop-Vac," said Smith.

Keep it handy. Brown marmorated stink bug numbers could get out of hand. Like many non-native species in the U.S., the brown marmorated bug left natural enemies behind. For many stink bugs, an important natural enemy is a species of parasitic wasps that attack eggs.

Kuhar said Virginia Tech graduate student Amanda Koppel recently traveled to China in search of natural "egg parasitoids" (insects whose larvae kill their hosts).

Koppel worked with the federal Animal Plant and Health Inspection Service and brought back "a parasitoid species, which could become a biological control agent for release in the future," said Kuhar.

Of course, another imported exotic species could cause another stink, so thorough research will occur before its use, he said.

Until then, homeowners can take a tip from Mel Gibson's alien-fighting character in the movie Signs. Use caulk, steelwool, screening and other materials to plug possible entry spots.

With one big cautionary note: Don't seal up the house after the bugs have entered or before they exit come spring. Dead insects inside the house can lure another troublemaker that dines on their husks -- carpet beetles.

And according to a Virginia Cooperative Extension Web page, "Carpet beetle larvae often wander about the infested location -- from room to room in a house."

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