Is Your House Bugged?

October 8th, 2008

Bugs in the garden are bad enough.

But when they come after you inside, too… well, that’s really getting personal.

For years, midstaters have battled indoor fall invasions of boxelder bugs and multi-colored Asian lady beetles – pests that try to survive winter by shacking up in your heated house.

Now a third and even uglier pest is driving us buggy – the brown marmorated stink bug.

This Asian import – first noticed in 2000 in Allentown – is brown in color, three-quarters of an inch in size and shaped like a shield.

Like Asian lady beetles, stink bugs overwinter in south-facing rock cliffs in their native habitat.

Here’s the problem: your neighborhood probably doesn’t have any cliffs.

“What happens is they see your house and think it’s a cliff,” says Penn State urban entomologist Steve Jacobs.

This time of year, you might find any or all of these three bugs swarming on warm west or south house walls looking for a way to get in.

A fourth up-and-coming indoor invader is the western conifer seed bug. (See the sidebar for more on all of these.)

If these bugs can find a crack, they’ll set up shop inside your walls. On sunny fall, winter and early-spring days, they’ll swarm in the living space, thinking it’s time to get busy again.

People often complain about hordes flying around lights or dropping into their cereal bowls.

“I’ve seen cases so bad that you have to keep your mouth shut or they’ll fly in,” says Jacobs. “I’ve seen people sweep buckets of beetles off the porch.”

Jacobs himself has done battle with indoor stink bugs.

“I used to live in a 150-year-old farmhouse, and I’d keep an old vacuum cleaner handy to suck them up,” he says. “They’d dive-bomb me every morning when I was combing my hair.”

All of these bugs are relatively harmless inside, although lady beetles can sometimes prick people in search of moisture and can cause respiratory and skin allergies.

They don’t eat human food, they don’t damage wood and they don’t sting.

They’re mainly a nuisance.

What to do?

Jacobs says the best strategy is to keep bugs out in the first place.

That means sealing cracks with caulk, weather-stripping or foam. Look around windows, doors, pipe entries, holes in window screens, roof overhangs, around window air conditioners and so on.

“One of the most overlooked spots is under window sills,” says Jacobs. “These often aren’t caulked at all because it’s a place where water isn’t likely to get in.”

How about spraying bugs as they swarm on the outside walls?

“Bad idea,” Jacobs says. “You may stop some of them, but when you apply an insecticide, you’re usually not killing them right away. It may take hours or even days for them to die. Most of them end up dying inside the walls.”

Then you have dead beetles and bugs inside the walls, which is a favorite food of carpet beetles. That leads to more carpet beetles, and when they run out of bug carcasses, they’ll turn to eating carpet, woolens and other fibers in the house.

Store-bought insecticides also break down quickly, so they’re not effective for long.

Jacobs says the restricted-use pesticides applied by professionals kill faster and longer, but you’ll still probably need several applications.

How about using a power washer with hot or soapy water?

“Depending on how hot the water is, you may be able to cook some of them,” Jacobs says. “But these are tough, hard-shelled bugs. They’re like little tanks. A stream of water might blast them off the building, but it’s probably not going to kill them. You might slow them down a little, but you’re probably not going to stop them.”

Jacobs recommends vacuuming inside bugs by fastening a nylon stocking to the end of the tube with a rubber band. Suction will pull the bugs into the nylon inside the tube, then you can remove the trapped bugs for outside disposal or death at the end of a blunt object.

He doesn’t recommend spraying a pesticide inside.

Once again, you’ll leave behind dead bodies to encourage carpet beetles, plus expose yourself to chemicals.

Even if you use a “bug bomb” or fogger, it’s unlikely to affect still-hidden bugs that come out later once the air has cleared.

“A better idea is to try and find out where they’re coming out of the walls and tighten that up as much as you can,” says Jacobs. “That’ll trap them in the wall. At least that’s better than having them flying around the living room.”

Jacobs says attic-placed UV light traps with sticky cards also may help, at least with lady beetles. The lights draw the bugs, then the cards trap them.

These should be checked and cleaned every few days. They’re primarily available through pest-control companies for $150-$250 or online (search for “UV insect light traps.”)

Definitely do NOT use a bug zapper, advises Jacobs.

“These fry bugs, and they explode,” he says. “One study showed bits of flies flung 20 feet away.”

Personally, I’d prefer a whole, living stink bug.

SIDEBAR

The low-down on four bugs you might see trying to get inside your house this time of year:

* Boxelder bugs. Narrow, about one-half inch long, hard-shelled and black in color with red stripes on its back.

Outside, boxelders cause minor chewing damage to boxelder, maple, ash and some fruit-tree leaves.

They can stain things and produce a foul odor when crushed.

Not as bad lately inside as before, but they can still swarm mercilessly after a hot, dry summer.

* Multicolored Asian lady beetles. Rounded red, orange or yellow hard-shelled bugs about the size of half a small pea. Most have black spots but some are plain.

Outside, these are gardener allies, feeding mainly on pest bugs such as aphids and scale.

Inside, they’re our biggest nuisance because of the sheer number.

They sometimes prick skin and cause respiratory or skin reactions in allergic people. They also can stain and emit a foul odor when crushed.

Consider releasing these back outside after vacuuming.

* Brown marmorated stink bugs. Brown, three-quarters of an inch long and almost as wide, shaped like a mini shield.

Outside, these are fairly destructive garden pests in Asia, favoring such plants as soybeans, peaches, apples, legumes and even some ornamentals. Here, they haven’t become nearly as troublesome as, say, Japanese beetles.

Not as numerous inside as lady beetles, but they’re bigger and uglier and smell bad when crushed.

* Western conifer seed bug. Narrow bug with extra-long pair of lowest legs, brown backs, light-orange undersides, three-quarters of an inch long and makes a nasty buzzing sound.

Outside, it feeds on the seeds of Douglas firs, pines and a few other needled evergreens.

Not terribly widespread yet in the East, but a good bet to be our next indoor invader. Not as smelly or stainy as the others, but can swarm with the best.

For detailed fact sheets on these pests, go to http://www.ento.psu.edu/extension/fact_sheets.html and look under “Nuisance Pests.”