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Stink bugs out in force this fall

By Karen Gardner

Thursday - 10/23/2008, 9:09am  ET

Fall is pumpkins, apples and now, stink bugs.

Residents of rural and suburban areas have likely seen these brown, mottled, shield-shaped insects about the size of a dime. These insects are seeking warm places to hibernate and often end up inside homes in September and October.

"It got so bad, my recording for away messages had, 'If you're calling about stink bugs, call this number," said Susan Trice, horticulture educator for the Frederick County Cooperative Extension Service.

The brown marmorated stink bug, native to Asia, got its name because of the pungent odor it gives off if stressed or squished. Scent glands on the abdomen and thorax cause the odor.

"They're plant pests," said Mary Kay Malinoski, an entomologist at the University of Maryland Cooperative Extension Service Home and Garden Information Center.

"They're strictly plant feeders. They're not like flies, feeding on dog poop. There's no potential to spread disease," she said.

The insects are not a public health threat, but that doesn't mean people don't want to get rid of them.

"The first thing people have to do is look at where they're coming in," said George Hamilton, an entomologist with Rutgers University in New Brunswick, N.J. Hamilton has been studying stink bugs for several years and is an expert.

"Caulk and seal around the windows," he said. "Look at attic vents. You should have fine screening."

Stink bugs were first confirmed in Allentown, Pa., in 2001, although they've been around in this region since about 1996, Hamilton said.

"I think they're going to be with us for a while," he said.

This year's population is especially large. "I'm not sure why. We had a mild winter and a mild summer, and that may be contributing."

The bugs are concentrated in Pennsylvania, New Jersey and Maryland, especially in the Western part of the state, he said.

Stink bugs, like many species that are transported from their native environments, do not have any predators in this country. In China, stink bugs are an agricultural pest, feeding on apples, grapes, peaches, other fruits and soybeans. But China also has predators that consume stink bugs.

"We think they came here in shipping material from China or Japan or Korea," Hamilton said.

They are spreading into Virginia, Ohio, New York and Massachusetts. One stink bug has been confirmed in Mississippi, while others have been spotted in Los Angeles County, Calif., and Portland, Ore.

"It may be a bigger problem," Hamilton said. "We just don't know it yet."

At this time, he said, they're not an agricultural pest, although they've been known to feed on snap beans, tomatoes, peppers and sweet corn if the kernels are exposed.

Damage to vegetable and fruit plants is minimal, as far as scientists can determine, Malinoski said. "They might leave a white spot, and some disfiguring," she said.

Stink bugs live outdoors in summer. They are especially attracted to rural and suburban yards with crabapple trees, pyracantha bushes, hollies and hawthornes.

To rid the yard of stink bugs, Hamilton recommends spraying the bugs outdoors with pyrethroid, a fairly mild insecticide that is effective in killing them.

Jim Fredericks is a technical director and entomologist with Home Paramount, a local pest control company. He said his company has received many calls on the bugs. But once the bugs have crawled into the walls of the house, he tells homeowners they need to wait until next year to treat the yard for stink bugs.

"We can kill them in the walls, but it's not a good idea," Fredericks said. Dead bugs attract other bugs that like to consume insects, and that could bring about a worse problem, he said.

"Our best advice is to vacuum them up," he said. "They're similar to the Asian lady beetles that overwinter in people's homes."

Trice recommends vacuuming the insects with a shop-vacuum. The bugs continue to secrete odors while inside vacuum bags, which could mean lots of vacuum bag changes.

The slow-moving insects are easy to capture, and they do not reproduce in winter. They also do not bite people or pets. Come spring, they move outside again.

Copyright 2008 The Frederick News-Post. All rights reserved.