Wikipedia says the brown marmorated stink bug, the one that moves into North American houses each fall, smells like cilantro. Wikipedia also says that for some people, because of variation in a gene called OR6A2, cilantro itself tastes soaplike or rotten. We are not claiming those two facts are related. We are claiming they are both on Wikipedia, and one of them is in your kitchen.
The short answer
Cilantro, mostly, and not in a good way. The brown marmorated stink bug, the one that invades North American houses, has an odor attributed to two aldehydes, trans-2-decenal and trans-2-octenal, that Wikipedia says has been characterized as a pungent odor that smells like cilantro. Ohio State Extension says pungent and acrid. Other stink bugs are described as oily, dusty, woody or earthy.
Interactive, 6 responses
The Stink Bug Response Desk 🪲
There is a stink bug on your wall. Choose a response. We will tell you what it costs.
The bug is not moving. Neither are you. Pick a response.
Cilantro Units are a joke scale and the numbers are ours. The facts under each response come from the source named there. This is a humor page, not pest control, medical or safety advice.
What the record says it smells like
Five descriptions from extension services, the EPA and Wikipedia, with the quotation marks only where the wording is verbatim from the page listed under Sources.
“pungent odor that smells like cilantro”
The most quoted comparison, and the only one on this list that a salad can be blamed for.
“a characteristic pungent acrid odor that many people find offensive”
Extension services write in a register where a smell is a characteristic. Nobody does disapproval better.
“an unpleasant odor”
A federal agency's whole review of the matter, delivered at the length of a parking ticket.
“oily, dusty, woody and earthy, and like coriander”
The composition varies between species and even by sex or age, so a stink bug's smell has a demographic. We have not been able to find out which one is the dusty one.
“a rancid almond scent”
Wikipedia says in some species the liquid also contains cyanide compounds. It is on the list because it is the most alarming sentence in this report, and the bug in your house is not that one.
Why a bug smells like an herb
Wikipedia attributes the brown marmorated stink bug's odor to trans-2-decenal and trans-2-octenal. The ending -enal marks both as aldehydes, and Wikipedia says the spray of stink bugs in general includes aldehydes and alkanes. Its coriander article says the dominant flavorants in cilantro leaves are the aldehydes 2-decenal and 2-dodecenal. The first names match apart from a prefix describing the shape of the molecule. We will not say the bug and the herb contain the identical molecule, only that they draw on the same family of chemistry, which is why people keep reaching for the same word.
The word may even be a bug joke from antiquity. Wikipedia says coriander comes through Old French and Latin from the Ancient Greek koriandron, possibly derived from or related to kóris, a bed bug, and given on account of its fetid, bug-like smell. That is a bed bug rather than a stink bug, but a language got to the idea long before a hardware store sold a vacuum for it.
Then there is the soap. Wikipedia says the gene OR6A2 sits in a cluster of olfactory receptor genes and encodes a receptor highly sensitive to aldehyde chemicals, and that people who dislike cilantro are sensitive to its unsaturated aldehydes. Reported dislike rates are 21% of East Asians, 17% of Europeans and 14% of people of African descent, but only 7% of South Asians, 4% of Hispanics and 3% of Middle Eastern subjects, groups where cilantro is a staple.
The tempting question is whether people who taste soap in cilantro smell something different in a stink bug. It is a reasonable guess, and it is a guess: none of the sources behind this page say it, so we are not claiming it. If you know of a paper, we would like to read it.
Does the smell hurt you?
Mostly no. UC IPM says brown marmorated stink bugs are not harmful to people, houses or pets, and that they do not bite, sting, suck blood or spread mammalian diseases. The EPA and Ohio State Extension also say they do not bite people or pets. The problem is the smell, and a small asterisk on it.
- Allergy. The EPA says some people may be sensitive to allergens given off by the bugs. Penn State Extension says the defensive chemicals can be an aeroallergen causing rhinitis or conjunctivitis in sensitive people, especially people sensitive to cockroaches and lady beetles.
- Skin. Penn State Extension says a bug crushed against exposed skin can cause dermatitis at the point of contact, and that it seems to affect only a small percentage of people.
- Eyes. Wikipedia says the body fluids are toxic and irritating to human skin and eyes, that reports on human cases are rare, and that one case of keratitis has been reported in Taiwan. Consider this the official reason not to wipe your face after step two of the Response Desk.
This is a humor page, not medical advice. If you react to anything, ask a doctor.
Why one is on your wall in November
Penn State Extension says adults begin searching for overwintering sites from September through October, and are attracted to the outside of houses on warm fall days. UC IPM says they congregate in late summer and early fall, then hide in narrow spaces indoors, including cracks under or behind baseboards. In winter the adults do not reproduce and feed minimally if at all, and a stink bug will not reproduce inside a structure or damage it. The bug is not infesting you. It is camping.
How it got here
- September 1998. A brown marmorated stink bug is collected in Allentown, Pennsylvania, where it is believed to have been accidentally introduced. Muhlenberg College students reportedly saw them as early as August of that year. Penn State Extension thinks it probably arrived several years before the first collection.
- 2010. In the Mid-Atlantic, $37 million in apple crops are lost, and some stone fruit growers lose more than 90% of their crops.
- November 2011. The bug has reached 34 US states. By 2012 it is in 40, and by October 2014 Wikipedia counts 41 out of 50.
- March 2018. The New Yorker publishes Kathryn Schulz's “When Twenty-Six Thousand Stinkbugs Invade Your Home.” The title is the report.
Wikipedia says it is believed to have hitched a ride as a stowaway in packing crates or on machinery, and it has behaved like one ever since: it turns up uninvited, it hides in the walls, and it does not pay rent.
Not every stink bug is a stink bug
Wikipedia says “stink bug” is also used for unrelated insects such as pinacate beetles, the genus Eleodes, also called desert stink beetles. They produce a quinone or a similar substance as a deterrent, and many species stand on their heads to spray it. Wikipedia describes the headstand as aposematic: it makes the beetle's presence and identity unambiguous, so predators learn to leave it alone.
It does not always work. Wikipedia lists owls, foxes, coyotes, bats, turtles and skunks among the animals that still eat them. The beetle does a handstand to announce it smells bad, and the number one entry on our Smell Index eats it anyway.
In Taxco, they hold a festival for them
Jumiles are small stink bugs native to the Taxco region of Guerrero, Mexico. Wikipedia says the jumil season begins on November 1 with a large fiesta in Taxco, where people gather in the mountain park of Huisteco to collect jumiles and to crown a Jumil Queen. Jumiles can be roasted, fried, ground or eaten raw, and a salsa is made by mashing them in a molcajete with fresh tomatoes, chiles and onions, served with corn tortillas.
They have a cinnamon-like odor, and Wikipedia calls them an acquired taste because their high iodine content gives a bitter, medicinal flavor. The local species is collected on purpose. It is not the one from your windowsill, whose body fluids Wikipedia describes as irritating to the skin and eyes, so this is not a suggestion.
Questions people ask with a tissue in hand
What do stink bugs smell like?
Wikipedia says the brown marmorated stink bug's odor, which is due to trans-2-decenal and trans-2-octenal, has been characterized as a pungent odor that smells like cilantro. Ohio State University Extension calls it a characteristic pungent acrid odor that many people find offensive. Across the whole stink bug family, Wikipedia lists oily, dusty, woody, earthy and coriander-like, and at least some species are described as having a rancid almond scent.
Do stink bugs only stink when squished?
No. Wikipedia says the name refers to the pungent defensive spray released when the bug is threatened, disturbed or crushed, and that simply handling the bug, injuring it or attempting to move it can trigger the odor. A stink bug left alone has nothing to release.
Why do stink bugs smell like cilantro?
They share a chemical family. The stink bug odor is attributed to trans-2-decenal and trans-2-octenal, which are aldehydes, and Wikipedia says the dominant flavorants in cilantro leaves are the aldehydes 2-decenal and 2-dodecenal. The word coriander may even come from the Greek for a bed bug, given on account of the herb's fetid, bug-like smell.
Can stink bugs stink up a room?
Usually the response does that, not the bug. Penn State Extension says that if many of them are crushed or sucked into a vacuum cleaner, their smell can be quite apparent. A bug that is left alone does not release the spray.
Is it bad to breathe stink bug smell?
For most people it is a nuisance. The EPA says some people may be sensitive to allergens given off by the stink bugs, and Penn State Extension says the defensive chemicals can be an aeroallergen, causing rhinitis or conjunctivitis in sensitive people, including people sensitive to the odors of cockroaches and lady beetles. If a smell makes you ill, ask a doctor, not a joke website.
Do stink bugs bite?
The sources we checked say no. The EPA and Ohio State University Extension say brown marmorated stink bugs do not bite people or pets, and UC IPM says they do not bite, sting, suck blood or spread mammalian diseases. Their mouthparts are for piercing plants. Wikipedia adds that the body fluids are irritating to human skin and eyes, which is not a bite but is also not a hug.
Will my vacuum smell of stink bugs?
Probably, for a while. The EPA says the vacuum may smell of stink bugs for a period of time. UC IPM says the bugs will make the canister, bag and other parts give off an unpleasant stink bug odor, so some people dedicate a vacuum cleaner to stink bug capture only, and it describes a nylon stocking over the end of the vacuum tube so the bugs land in the stocking and not the bag.
Where do stink bugs come from?
The brown marmorated stink bug is native to China, Japan, Korea and other Asian regions. It was collected in Allentown, Pennsylvania in September 1998, where it is believed to have been accidentally introduced, and Wikipedia says it probably hitched a ride as a stowaway in packing crates or on machinery. Penn State Extension says it probably arrived several years earlier than that first collection.
What do stink bugs eat?
Plants. Wikipedia says the nymphs and adults feed on over 100 species of plants, using a proboscis to pierce them and suck sap, including peaches, apples, green beans, soybeans, cherries, raspberries and pears in the United States. Indoors in winter, UC IPM says feeding, if any, is minimal and the adults do not reproduce.
More field reports
Stink bugs are not on the Stenchi Smell Index, which is ten harder cases. These are the other reports from the Odor Research Division.
Sources
- Wikipedia: Brown marmorated stink bug
- Wikipedia: Pentatomidae
- Wikipedia: Coriander
- Wikipedia: Jumiles
- Wikipedia: Eleodes
- UC Statewide IPM Program: Brown Marmorated Stink Bug
- US EPA: Brown Marmorated Stink Bug
- Penn State Extension: Brown Marmorated Stink Bug
- Ohio State University Extension: Brown Marmorated Stink Bug (ENT-90)
Quotations are verbatim from the pages above. The Kathryn Schulz article is cited by title and date as listed in Wikipedia's Pentatomidae article. The jokes, the Response Desk, the Cilantro Units and the Stenchi products are ours. This is a humor page, not pest control, medical or safety advice. Stenchi products are fictional and cannot be bought.
Pass it on