A brown marmorated stink bug (Halyomorpha halys) invasion of your home is an aggravating and embarrassing occurrence. After feeding on plants in your landscape during the warm months, these pests, which release an offensive odor when disturbed, gravitate toward the warmth and protection of the indoors in the fall. Your best line of defense when it comes to brown marmorated stink bugs (BMSB) is understanding them.
About 250 native stink bug species exist in North America, but they are generally kept under control by native predators. The foreign BMSB, on the other hand, has no native predators to keep it in check and is therefore highly invasive, indoors and out.
Imported accidentally from Asia, the foreign BMSB is believed to have arrived in North America in the 1990s. It was first sighted in Allentown, Pennsylvania, in 1998, but believed to have arrived a few years prior.1 With plenty of vegetation to eat, and the absence of natural predators, this voracious bug quickly became a nuisance pest in landscapes and homes. By 2011, the pest had caused significant damage to agricultural crops throughout most Mid-Atlantic states.2
The adult marmorated stink bug has a shield-shaped, mottled-brown body about 1/2-inch long. Its antennae, legs and the edges of its abdomen feature white banding. Stink bugs mate in spring and the females lay oval, white to light green eggs in clusters on leaves from June through September.3 Stink bug nymphs (young) pass through five phases, known as instars, prior to becoming adults. As they grow, they shed their outer skin and eventually emerge as full-sized adults.1
In cold Mid-Atlantic States, the stinkbug produces just one generation per year, but in subtropical areas of China, where the bug originates, it can produce four to six generations in one year.2 In warmer North American regions, such as the south, the bug produces two or three generations per year.3
When temperatures dip in fall, BMSBs seek shelter and warmth indoors. Stink bugs don't damage your home, but they are bothersome. In addition to releasing foul odors, they fly around when exposed to light. They also usually infest in great numbers. For instance, a senior scientist at the National Wildlife Federation caught 20,000 stink bugs in his home from January through March 2011.4
Brown marmorated stink bugs gather in large numbers because of pheromones. Once comfortable in your home, they release a scent that invites other stink bugs to join them.5 The odor of pheromones is different from the stench of the stink bugs' secretions that are released when the pests are disturbed. The secretions create airborne chemicals known as aeroallergens, which can cause reactions in individuals prone to allergies. Skin contact with a stink bug can also cause dermatitis.1
To keep stink bugs out, use polyurethane insulating foam sealant, which expands, to fill in holes around the home that are larger than the size of the bugs. These include gaps and cracks around doors, window frames, utility lines, pipes and your chimney. Check the integrity of all screens, including those covering vents, and replace if necessary. Add weather stripping around windows and doors, and check that siding and fascia is secure.1
For added protection, spray Amdro Quick Kill Outdoor Insect Killer (RTS) around the perimeter of your home. This will help control the insects outdoors, so they are less likely to sneak indoors.
If stink bugs outsmart you and make their way indoors, they will generally take up residence in wall voids, entering rooms from under baseboards and from around ceiling lights and other openings. If you haven't already sealed these areas, do so. Bugs that have entered should be killed outdoors, where the smell will quickly dissipate. Vacuuming them up is an effective removal method, but you'll likely want to throw the bag away when done.1
Stink bugs in your home can cause frustration. Armed with this knowledge about their living habits and the various ways they enter your house, you can protect your home against these smelly invaders.
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1. Steve Jacobs, "Brown Marmorated Stink Bug, Halyomorpha halys," Penn State College of Agricultural Sciences, February 2015
2. "Origins of BMSB," Stop BMSB
3. Jamba Gyeltshen, et al., "Brown Marmorated Stink Bug," University of Florida Entomology and Nematology, June 2013
4. "Brown Marmorated Stink Bug," National Wildlife Federation
5. Collin R. Marchiando, "General Brown Marmorated Stink Bug Information," Rutgers New Jersey Agricultural Experiment Station