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How to identify it
- Adults are about 17 mm (0.66 inch) long, shield shaped and mottled in shades of brown.[1][2]
- Look for light bands on the antennae and dark bands on the overlapping rear part of the wings, plus coppery or bluish metallic pits on the head and pronotum. Minnesota describes alternating dark and light bands on the antennae and abdomen and a smooth, rounded shoulder; Clemson describes distinct black and white antennal bands, rounded shoulders behind the head and a brown-gray to bluish-gray underside.[1][2][4]
- Eggs are laid side by side on the undersides of leaves, in masses of 20 to 30 (Penn State) or fewer than 30 (Clemson). Penn State describes them as light yellow to yellow-red and Clemson as light green. Clemson says a female may lay nearly 500 eggs in her lifetime.[1][4]
- There are five nymphal stages, from 2.4 mm long in the first to 12 mm in the fifth. Nymphs have black heads and legs and deep red eyes; Minnesota says newly hatched nymphs have a yellow-red abdomen, older ones are darker, and none have wings yet.[1][2]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Native stink bugs | Several native stink bugs can be confused with it. Check the antennae for the light and dark bands and the shoulders behind the head, which are smooth and rounded on the brown marmorated stink bug. Minnesota also points to alternating light and dark bands on the abdomen.[4][2][1] |
Where it lives
First found in Allentown, Pennsylvania, in 1998 and now in most of eastern and western North America.[1]
Biology and life cycle
Penn State says it probably has one generation a year in Pennsylvania, though warm springs and summers may allow two. Adults emerge from late April to mid-May, lay eggs from May through August, and look for overwintering sites in September and October. Minnesota reports a partial second generation there, and Clemson says it may have several generations a season depending on location.[1][2][4]
It feeds on a wide range of fruits, vegetables and ornamental plants, causing "cat-facing" on apples and peaches. Minnesota says nymphs and adults feed on more than 200 kinds of plants and that feeding on developing fruit can cause seed abortion, discoloration and deformation; Clemson says heavy feeding leaves the fruit surface depressed, spongy and often discolored.[1][2][4]
In Minnesota, numbers are highest from mid-August through October. Cooler temperatures send adults looking for winter shelter, especially in older buildings where windows may not be sealed.[2]
Outdoors, Clemson says they overwinter in dead standing trees with thick bark, such as oaks and locust, but not in fallen trees or leaf litter. In buildings they settle around windows and baseboards, in attics and in almost any void.[4]
Sources give different first-detection dates. Penn State and Clemson say it was first collected in Allentown, Pennsylvania, in 1998 (Penn State adds that it probably arrived several years earlier), while a 2012 report by Penn State dermatologists says it was first found in Allentown in 1996. Clemson's 2014 fact sheet says it first appeared in South Carolina in 2011 and had been confirmed in 41 states and part of Canada.[1][4][5]
Damage and signs
- Indoors it does not reproduce or damage the structure, but crushed or vacuumed bugs release a strong odor. Minnesota says that over the winter they do not lay eggs, reproduce, damage homes or bite.[1][2]
- In vineyards, bugs tucked into grape clusters at harvest can release chemicals that taint the wine, which Minnesota says may be a bigger concern than the feeding itself.[2]
Health risk
In 2012, Penn State dermatologists described irritant contact dermatitis from the brown marmorated stink bug and noted that fruit crop workers have complained of a slight allergic reaction to the chemicals it releases; the same report found no published cases of human disease from it. A 2012 report in the Journal of Allergy and Clinical Immunology described the bug as a new aeroallergen.[5][6]
Control
Keep them out
Before fall, seal cracks around windows, doors, siding, utility pipes, chimneys and fascia with good-quality silicone or silicone-latex caulk, and repair screens. Clemson adds weather stripping around doors, windows and garages, tight screens on eaves, soffits and attic openings, sealing where telephone, cable and electric lines enter, and a chimney damper that closes tightly. Minnesota says to check where cords, pipes and cables enter the house.[1][4][2]
Traps and physical control
Vacuum live and dead bugs indoors (the vacuum may smell for a while), and caulk the gaps where they emerge, such as around baseboards, trim and ceiling fixtures. Minnesota suggests emptying a shop vacuum into a bucket of soapy water or releasing the bugs outside; Clemson says to dispose of the vacuum bag in a sealed container.[1][2][4]
Pesticides
Exterior treatments by a licensed applicator just before bugs gather give only minor, short-lived relief. Don't treat wall voids or attics: dead bugs can feed carpet beetles, and foggers don't stop more from emerging. Sunlight breaks exterior insecticides down: Penn State says the residue may not kill much beyond several days or a week, and Clemson says it breaks down quickly from sunlight and moisture unless well placed. Minnesota says the bugs' biology makes insecticides hard to use against them, so physical removal works better, and it does not recommend pesticides indoors.[1][4][2]
When to call a professional
If the problem is bigger than a vacuum can handle, Clemson suggests calling a pest management professional.[4]
More from UMN Extension
The stink bug arrived from Asia undetected in the 1990s and was first found in Minnesota in 2010.[2]
The Minnesota Department of Agriculture tracks it, and it has been found in many parts of the state. Its North American range includes the Eastern and Midwestern United States and Canada.[2]
Common questions
- Will stink bugs breed in my house?
- No. They overwinter indoors but don't reproduce or damage the structure. Minnesota says that during the winter they do not lay eggs or reproduce.[1][2]
- Should I bug-bomb the attic?
- No. Foggers won't stop bugs emerging from walls, and dead bugs in voids can feed carpet beetles.[1][2]
- Do brown marmorated stink bugs bite?
- No. Minnesota says they don't bite. The concern is their defensive chemicals: a 2012 dermatology report described irritant skin reactions and slight allergic complaints among fruit crop workers.[2][5]
- When do stink bugs come into houses?
- In fall. Penn State says adults look for overwintering sites in September and October, and Minnesota says numbers peak from mid-August through October, with bugs gathering on the sunny sides of buildings.[1][2]
Sources
- Penn State Extension, “Brown Marmorated Stink Bug (revised December 2017).” extension.psu.edu/brown-marmorated-stink-bug (accessed 2026-11-11)
- University of Minnesota Extension, “Brown marmorated stink bug.” extension.umn.edu/garden-and-home/yard-and-garden/yard-and-garden-insects/brown-marmorated-stink-bug (accessed 2026-11-11)
- iNaturalist, “Halyomorpha halys taxon page (order and family).” www.inaturalist.org/taxa/81923 (accessed 2026-11-11)
- Clemson Cooperative Extension Home and Garden Information Center, “Brown Marmorated Stink Bug in Structures (HGIC 2404).” hgic.clemson.edu/factsheet/brown-marmorated-stink-bug-in-structures/ (accessed 2026-11-11)
- Dermatitis, via PubMed, “Anderson et al. (2012), Irritant contact dermatitis to the brown marmorated stink bug, Halyomorpha halys, Dermatitis 23(4):170-172.” pubmed.ncbi.nlm.nih.gov/22828257/ (accessed 2026-11-11)
- Journal of Allergy and Clinical Immunology, via PubMed, “Mertz et al. (2012), The brown marmorated stinkbug as a new aeroallergen, J Allergy Clin Immunol 130(4):999-1001.” pubmed.ncbi.nlm.nih.gov/22835402/ (accessed 2026-11-11)