Stink bugs are on the march.



The shield-shaped pests are making a nuisance of themselves this fall, crawling into homes in unprecedented numbers.



So far reports to Ohio State University extension offices about the insects have been patchy around the state. But insect expert Dave Shetlar thinks that when the first frost hits, many of us will find the bugs invading our homes in search of a warm place to spend the winter.



The culprit is the brown marmorated stink bug, or Halyomorpha halys, an Asian species that’s relatively new to our area. It was first reported in the United States in 1998 and was found in Ohio in 2007.



So far this fall, the OSU Extension office in Summit County hasn’t received any calls from homeowners asking about the bugs, said Danae Wolfe, its agriculture and natural resources educator. But “I’ve been seeing a lot of them,” especially in the last two weeks, she said.



On the other hand, Shetlar, who works with the OSU Extension in Columbus, has had three emails from panicked homeowners saying their homes have been overrun. Extension agent Tim Malinich reported seeing an arborvitae in Northeast Ohio that was covered so heavily with the bugs that it appeared to be moving.



The brown marmorated stink bug grows to about ?-inch long and has a shield-shaped body in marbled shades of brown. True to its name, it raises a stink when it’s squeezed or squashed that some people liken to smelly feet.



Eww.



No one knows how the bugs got here, but Shetlar supposes they arrived inside a shipping container. Their numbers have grown because their enemies, including parasitic wasps that attack the bugs’ eggs, can’t keep up with them, he said.



The insect is more of a problem in farm fields and gardens than in homes, Shetlar said. It feeds on a range of ornamental and food plants, he said, and researchers are still assessing the damage it can do to fruit and soybean crops.



In the house, it’s little more than an annoyance, Shetlar said. It won’t bite, sting or cause damage, but it can invade in large numbers — hundreds, in extreme cases, according to an OSU fact sheet.



The bugs get in through tiny cracks, holes and other openings in a home’s exterior.



“These aren’t Houdini bugs,” Shetlar said. “They don’t just magically appear in your house.”



Windows that seal poorly are a common entry point, he said. So are soffit and roof vents where the screening has broken down. Often they’ll emerge from behind baseboards, window or door trim, exhaust fans or ceiling lights.



Both the Ohio State and Penn State extensions say keeping the bugs out is the best approach. Repair or replace damaged window and vent screens, remove window-mounted air conditioners, replace worn door sweeps and weatherstripping, and seal openings with caulk or foam.



Neither extension service recommends using pesticides indoors. Bug bombs don’t seem to work, Shetlar said, and most pesticides approved for indoor use won’t remain effective long enough to halt an infestation.



Shetlar said he just picks up the stink bugs he finds and tosses them outside. You can suck them up with a vacuum cleaner, but use the toe of an old stocking to create a pouch between sections of the hose so the bugs don’t stink up your vacuum.



More on the brown marmorated stink bug can be found at http://ohioline.osu.edu (search for “stink bug”).



Mary Beth Breckenridge can be reached at 330-996-3756 or mbrecken@thebeaconjournal.com. You can also become a fan on Facebook at http://tinyurl.com/mbbreck, follow her on Twitter @MBBreckenridge and read her blog at www.ohio.com/blogs/mary-beth.