INDIANAPOLIS — Just like most of the rest of us these days, stink bugs are waking up from a long, nasty winter — perhaps in your attic or behind walls near the top of your house — and beginning to move around.
If you live in a drafty old house, you're probably seeing them everywhere, now that sunlight is brighter, stronger and warmer.
From a homeowner's perspective, stink bugs "are active in March and April and very active in September when they're trying to get into your house," says Cornell University entomologist Peter Jentsch, the Hudson Valley expert on all things stink bug.
Related: 10 things to know about stink bugs
The good news is that now that they're awake and active again, they're looking for a way to get back outside. "They will find their way out or die," says Jentsch, who is based at the Hudson Valley Research Laboratory in Highland.
"The majority of the population lives in the tree canopy year-round, or in the fall they head for man-made sites like commercial buildings or your house," he says.
Once they find their way in, in the fall, stink bugs tend to head toward the attic. They may settle in stacks of newspapers or piles of clothes.
Stink bugs are a nuisance indoors, but otherwise harmless to humans, Jentsch emphasizes. "They eat nothing, they don't bite, they're just trying to survive."
Who are they?
According to North Dakota State University, there are 4,700 species of stink bugs in the world, with about 250 in the U.S. and Canada. Our pest is known as the brown marmorated stink bug (Halyomorpha halys). It gets its name from the brown marbling pattern on its back.
To identify them, look for striping on its antennae, a striped pattern along the abdomen and smooth shoulders. It has a five-sided, shield-shaped body and is about 3/4 of an inch long.
Why are they stinky?
When squashed, frightened or disturbed, stink bugs secrete a foul-smelling, bad-tasting substance.
Be careful about vacuuming them up in a household vacuum cleaner because the strong odor will remain. Use a shop vac, and take it outside right away, if you go that route.
How did they get here?
Native to China, Japan, Korea and Taiwan, brown marmorated stink bugs have been in the Hudson Valley since 2007. In the United States, they were first documented in Allentown, Pa., in the mid-1990s. They probably hitched a ride in shipping containers, just like the Asian longhorn beetle that has killed millions of trees nationwide. Stink bugs are now in more than 30 states.
What do they eat?
Stink bugs are a serious pest, feeding on a long list of host plants, including fruits, vegetables, ornamentals and legumes. They also feed on weeds and tree leaves, and are comparatively impervious to insecticides.
To feed, the bug punctures agricultural products with a straw-like appendage and withdraws sap containing water, protein and carbohydrates.
In agriculture, stink bugs have been more of a problem in Mid-Atlantic states like Delaware, Maryland and Virginia. The U.S. Apple Association estimated that stink bugs caused $37 million in damage to apple growers in Maryland, Pennsylvania, Virginia and West Virginia in 2010.
They have also been a real headache for home gardeners in these states.
If you have an indoor problem with stink bugs, it may because of the types of trees surrounding your house. They tend to like to eat the foliage and seeds of black locust, maple, ash, Ailanthus altissima (tree of heaven) and catalpa trees.
How do I kill them?
For homeowners, Jentsch suggests a simple, nontoxic brew of soapy water (1% to 2% soap to water) in a household spray bottle. "That will probably work as well as anything."
"This time of year, if you blow at them the wrong way they'll die," he says, partly in jest, explaining that they haven't eaten anything in six months.
In the field, "the insecticides that tend to work are the older chemistries," Jentsch says. In agricultural settings in the Hudson Valley, an effective way to control them has been with trap and kill stations, using pheromone traps as a lure. That way, farmers and orchard growers don't need to spray insecticides on the crops as frequently.
How do I keep them out of my house?
Prevention in the fall is key. "Once established in your house, it's nearly impossible to get rid of them," Jentsch says.
Seal all cracks around windows, doors, siding, utility pipes, behind chimneys and underneath the wood fascia and other openings with high quality silicone or silicone-latex caulk.
Remove wall and window air conditioners; weather stripping around doors and windows may help. Repair broken screens and windows.
"You have to think like an insect," Jentsch says.