The brown marmorated stink bug (Halyomorpha halys) is an invasive species originally from Asia.
It has become a significant agricultural pest in the United States since its first discovery in Pennsylvania in the late ’90s.
These bugs are known for their distinctive shield shape and brown mottling, as well as the unpleasant odor they release when disturbed.
The life cycle of the brown marmorated stink bug is an important aspect to understand in order to manage their impact on agriculture.
The bugs go through five nymphal stages before reaching adulthood. Their development is heavily influenced by temperature and food availability.
Adult female stink bugs lay clusters of 20-30 light green or yellow, elliptical-shaped eggs on plant leaves and stems.
The eggs typically hatch within a week, and the emerging nymphs begin to feed on nearby plant tissues.
As they grow and molt through their various life stages, the nymphs cause significant damage to crops by piercing plant tissues and sucking out nutrients.
Brown Marmorated Stink Bug Overview
Origin and Distribution
The brown marmorated stink bug (Halyomorpha halys) is an insect species native to China, Japan, Korea, and Taiwan.
It was first introduced in the Eastern United States in the 1990s, and later spread to North America, Europe, and South America.
Appearance and Identification
This stink bug belongs to the family Pentatomidae and the genus Halyomorpha.
Adult brown marmorated stink bugs are shield-shaped with brown mottling, measuring between 14 and 17 mm long, roughly the size of a U.S. dime.
They have alternating broad light and dark bands on their abdominal edges and last two antennal segments1.
Invasive Species Status
Since its introduction, the brown marmorated stink bug has become an invasive species, causing damage to fruit, vegetable, and grain crops.
They have piercing-sucking mouthparts with a straw-like stylet that sucks plant juices2.
They prefer to feed on reproductive structures like fruits, pods, and seeds2.
Brown Marmorated Stink Bug Life Cycle and Development
Mating and Reproduction
The brown marmorated stink bug reproduces through mating.
- Mating: Triggered by pheromones released by the female
- Temperature: Higher mating activities during warmer months (May through August)
Brown marmorated stink bug (BMSB) females lay clusters of 20-30 light green or yellow, elliptical-shaped eggs on the underside of leaves and stems, from May to August.
The eggs are typically laid on the host plant, where nymphs will later feed.
Brown Marmorated Stink Bug Eggs and Hatchlings
After hatching, BMSB undergoes five nymphal stages, known as instars, before becoming adults.
Each instar lasts about one week, with the nymphs growing and molting at each stage. Nymphs have distinct characteristics:
- First instar: dark, with orange-red highlights
- Second to fifth instar: black and white striped antennae, and black and red abdominal markings
Nymphal feeding mainly focuses on the leaves, stems, and fruits of host plants.
Adult BMSBs reach a size of 14-17 mm long and have a shield-shaped body with brown mottling.
Their abdominal edges and last two antennal segments display alternating broad light and dark bands.
Adult BMSBs can live for several months, and their primary role is reproduction.
Throughout the spring and summer, adults feed on various plant species, contributing to their status as agricultural pests.
As temperatures drop in the fall, they seek shelter in buildings and other structures to overwinter.
Once in their overwintering locations, BMSBs enter diapause, a state of dormancy that helps them survive cold temperatures.
They become active again in the spring, continuing their lifecycle.
|Eggs||~1 week||Light green/yellow, elliptical-shaped|
|Nymphs||~5 weeks||5 instars, striped antennae, colorful markings|
|Adults||Several months||Shield-shaped, brown mottling|
Feeding and Host Plants
Types of Host Plants
Brown marmorated stink bugs have a wide range of host plants, usually feeding on foliage and fruiting structures. Their preferred host plants include:
- Tree fruits
The bugs’ hemimetabolous life cycle consists of eggs, nymphs, and adults.
Several generations may occur each year, depending on the availability of host plants.
Crop Damage and Agricultural Impact
The presence of brown marmorated stink bugs causes significant damage to agricultural crops.
They use their piercing-sucking mouthparts to consume plant juices, leading to visible changes in the plants:
- Leaves: chlorotic spots, necrosis, or leaf curling may occur
- Stems: deformation and necrosis can occur, impacting overall plant growth
- Fruit: damage ranging from dimpling to fruit collapse
Additionally, their feeding may lead to the transmission of plant pathogenic microorganisms.
The most significant crop damage typically affects field crops, vegetable crops, and tree fruits.
For example, hazelnut production faces challenges due to stink bug infestations.
Agricultural practices must actively monitor and manage these pests to reduce their impact on crop yield and quality.
Stink bugs are observed as a nuisance, especially when they invade buildings during overwintering. These pests can cause severe crop damage.
- Habitat: Fruit, vegetable, and grain crops
- Infestations: Damage plants by sucking plant juices
- Natural enemies: Predators, parasitoids, and diseases help limit population growth
Management and Control
Natural Enemies and Predators
One of the natural enemies of the brown marmorated stink bug (BMSB) is the Trissolcus japonicus, also known as the samurai wasp.
It is native to the same region as the BMSB and has been found in the Mid-Atlantic region of the United States.
This tiny wasp is an egg parasitoid that lays its eggs inside the BMSB’s eggs.
Some other predators of the brown marmorated stink bug include:
- Generalist predators (such as spiders and ladybeetles)
- Small mammals
Effective Pesticides and Solutions
When it comes to managing stink bugs, some effective pesticide options are available.
An example of a pesticide is Surround 95WP, which is an OMRI-listed organic option.
Other chemical options include Warrior II and Baythroid XL. Here is a comparison table showing the properties of each pesticide:
|Pesticide||Rate||REI (Hours)||PHI (Days)||Efficacy||Notes|
|Surround 95WP||25 to 50 lb.||4||0||Moderate||OMRI listed|
|Warrior II||1.3 to 2.5 fl. oz.||24||21||Moderate||Restricted Use Pesticide|
|Baythroid XL||1.4 to 2.8 fl. oz.||12||7||Moderate||14 days application interval|
Apart from chemical control, some non-chemical methods are also effective in controlling BMSB populations:
- Mechanical removal (using a vacuum cleaner or hand-picking)
- Exclusion techniques (sealing gaps and cracks in buildings to prevent entry)
- Monitoring and trapping (using pheromone traps)
The brown marmorated stink bug is a significant global issue as an invasive agricultural pest, impacting specialty crops, and as a nuisance when infesting buildings.
Proper management and control of this pest are crucial to minimize its impact on both crops and urban environments.
Other Relevant Information
Comparison to Native Stink Bugs
The brown marmorated stink bug (BMSB) differs from native stink bugs in the following ways:
- Size: BMSB is between 14-17 mm long, while native stink bugs vary in size
- Coloration: BMSB has brown mottling and alternating light and dark bands on antennae and abdominal edges, native stink bugs often have uniform colors
Impact on Specialty Crops
BMSB poses a threat to specialty crops, particularly:
- Tree fruit (apples, peaches, and plums)
- Citrus fruits
- Vegetables (tomatoes, bell peppers, and beans)
These insects feed on leaves, stems, fruits, pods, and seeds, causing damage and reducing crop yields.
Managing BMSB in orchards requires a combination of methods to avoid crop loss:
- Monitoring: Regularly observe for BMSB presence and damage, using traps can be helpful
- Physical controls: Install barriers or nets to prevent BMSB from reaching the crops
- Biological controls: Encourage natural predators, such as parasitic wasps, to control BMSB populations
- Chemical controls: Apply insecticides when BMSB populations reach damaging levels; follow guidelines to avoid harming beneficial organisms and the environment
Orchard management should be tailored to suit the specific crop, climate, and BMSB infestation levels.
The Brown Marmorated Stink Bug, an invasive species from Asia, has become a significant concern for agriculture in the U.S. since its introduction.
With its distinctive shield shape and unpleasant odor, understanding its life cycle is crucial for effective management.
From the laying of 20-30 elliptical-shaped eggs by females to the five nymphal stages leading to adulthood, these bugs have shown adaptability and resilience.
Their feeding habits, which involve piercing plant tissues and extracting nutrients, cause extensive damage to crops.
Effective management strategies, including the use of natural predators and specific pesticides, are essential to mitigate their impact on both agricultural and urban environments.
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about Brown Marmorated Stink Bugs. Scroll down to have a look at some of them.
Letter 1 – Brown Marmorated Stink Bug Hatchlings
newly hatched beetles (?) on rose bush
Location: Herndon, Virginia
June 15, 2011 7:09 pm
I was dead-heading one of my rose bushes & tossing the cut stems on the ground when I looked down & noticed this bunch of eggs in the process of hatching into orangish colored beetles on the underside of one of the leaves.
They don’t look loke anything I’ve found in any ”beetle egg ID” type sites, & I’ve never seen them before. (I figured if these were on my roses, they were probably up to no good, so after I took these photos the branch got put out in the street for the birds to play with) Thanks!
Signature: Lois in Virginia
You were luckless in your identification attempt because these are Stink Bug hatchlings, not beetles. We are happy we took the time to properly identify the species, which is often difficult with hatchlings, because these are newly hatched Brown Marmorated Stink Bugs, Halyomorpha halys.
We found a nearly identical photo on BugGuide. You may be familiar with the adults that often seek shelter indoors with the approaching cold weather. They are quite common in Maryland, probably the site of the original introduction of this exotic invasive species. We have a special page on our site to alert our readership about invasive exotic species.
You may find additional information on BugGuide including: “Elliptical eggs are laid in clusters, often on the underside of leaves. Five instars (nymphal stages) take about a week each; the nymphs typically being brightly colored with red and black. In PA, the BMSB has only one generation a year, like in the northern part of its native range.
However, in southern China up to five generations occur each year, and the same pattern can be expected as the bug spreads south (Hoebeke & Carter 2003, Hoffmann 1931). The adults mate in the spring about two weeks after emerging from diapause or the resting phase.
The females soon begin laying egg masses (at ~ weekly intervals); a female lays about 400 eggs in her lifetime. In PA, the egg-laying was observed from June to September, so different instars can be present on the same plant.
Eggs hatch after 4-5 days. Nymphs are solitary feeders, but occasionally aggregate between overlapping leaves or leaf folds (Bernon 2004). Adults are sexually mature two weeks after the final molt (Hoebeke & Carter 2003).”
The Brown Marmorated Stink Bug has already gotten a strong foothold on the east and west coasts, and we can expect it to soon spread to other parts of North America. You should dispatch these hatchlings without mercy, though that one instance on insecticide will hardly curb the spread of this noxious invasive pest.
We are also including a photo of the adult Brown Marmorated Stink Bug with this posting. The Brown Marmorated Stink Bug was selected as our Bug of the Month for October 2010 and it was a very popular posting.
Letter 2 – Brown Marmorated Stink Bug Hatchlings
Teeny Hatchlings on Rose Leaf
Location: Philadelphia, PA
June 15, 2011 10:44 pm
I found these little critters on the underside of a rose bush June 11, and they were actively hatching from their eggs. My thumb in the photo is a good point of reference for size. Any idea what they are?
We just finished, minutes ago, another similar posting which we identified as Brown Marmorated Stink Bug Hatchlings. You should read that posting for additional information and links.
We believe your newly hatched individuals will soon darken and here is an image on BugGuide that shows the pale coloration of hatchlings. The Brown Marmorated Stink Bug is an invasive exotic species and in our opinion, you should quickly dispatch these hatchlings if you want to prevent an invasion of your garden and your home.
Thank you so much! I’m a new convert to What’s That Bug. I’m so excited that all the bug photos I’ve been taking in my Philadelphia gardens are going to go to good use now.
The work/play that you’re doing with this website is invaluable. Keep it up!
Peas, love, & stinkbugs;
Letter 3 – Brown Marmorated Stink Bug Nymph
name that bug
Location: bel air maryland
July 30, 2011 2:40 pm
Found this creep on my deck…any help on what it is?
Signature: lisa c
We are terribly amused by your photo because this Brown Marmorated Stink Bug nymph appears to be mimicking the knot hole in your deck. Here is a photo from BugGuide for comparison.
According to BugGuide, the Brown Marmorated Stink Bug is: “native to Asia (a crop pest), adventive and spreading in NA: introduced near Allentown, PA now abundant from NJ to MD, also in OR, CA, WA.” We frequently get complaints from folks in Maryland that adult Brown Marmorated Stink Bugs enter homes in the fall to hibernate, sometimes in prodigious numbers.
Letter 4 – Brown Marmorated Stink Bug: Beautiful Photograph
Location: Mansfield, Ohio
February 23, 2013 8:24 pm
I apologize for sending my bug identification query with the wrong section of your site.
This is the insect; He has a one and a half inch or so thorax that is arrow shaped. His thorax is about a three quarters of an inch wide. His head is small and directly attached to his thorax. He has six legs.
He has wings but doesn’t appear to be capable of sustained flight. They appear in all parts of the house but mainly around windows. His back area is brown but speckled with gray.
We live in central Ohio and have had these little visitors since mid fall until now (late winter.)
Thanks bug guys!
This is a very artful photograph of a Brown Marmorated Stink Bug. If we ever do a calendar again, this would be a wonderful image of an invasive species that invades homes. Ground Zero for this Asian species is suspected to be Maryland.
It was a Bug of the Month several years ago and we have numerous other postings on our site. Just use our search engine to find all the Brown Marmorated Stink Bug postings. BugGuide has wonderful information on the Brown Marmorated Stink Bug or Interstate Bug or Asian Stink Bug.
Letter 5 – Brown Marmorated Stink Bug Hatchlings
Subject: eggs and babies
Location: Columbus, Ohio
June 17, 2013 5:06 am
Hi! I am hoping you can help me identify what I found on the underside of a peach tree leaf. I’ve never gotten peaches off the tree thanks to squirrels and am wondering if these bugs are horning in on the animals territory.
These are newly hatched Hemipterans, and we believe they are Stink Bugs in the family Pentatomidae. Further research indicates that they are most likely hatchlings of the invasive exotic Brown Marmorated Stink Bug, Halyomorpha halys. See this matching image on Featured Creatures where it states:
“The brown marmorated stink bug (BMSB), Halyomorpha halys Stål, is a pest that was first officially reported from the western hemisphere in Allentown, Pennsylvania in 2001 (Hoebeke and Carter 2003). This stink bug may become a major agricultural pest in North America, similar to the southern green stink bug, Nezara viridula (L.).
Both species are polyphagous pests of various crops, but in the U.S. it has been primarily reported as a household nuisance and ornamental pest. However, in eastern Asia where the BMSB is native or indigenous, it is a pest on fruit trees and soybeans.”
Thank you for letting me know–and so quickly too! This is a different stink bug than I have encountered before. I will have to get more vigilant now.
Letter 6 – Brown Marmorated Stink Bug Hatchlings
Subject: Beetle hatchlings
Location: Vancouver WA
July 5, 2013 5:09 pm
I found these guys recently hatched on one of my flower pots. I can’t for the life of figure out what they are. Closest I came was finding a post on Flickr from a few years ago in Blue Springs Missouri wondering about the same type of bug. I’m in the Pacific Northwest.
Can you tell me what they are?
These are not beetles. They are newly hatched Brown Marmorated Stink Bugs and this invasive, exotic species is spreading across North America. Normally, we do not endorse extermination, but this policy does not extend to invasive, exotic species. Squash them before they spread.
Letter 7 – Brown Marmorated Stink Bug Metamorphosis
Subject: Emerging stink bug
Location: Patapsco State Park, Maryland
September 3, 2013 11:29 am
Long time reader, first time submitter. I used your site and BugGuide to determine that this is an emerging brown marmorated stink bug, which in itself is not very exciting, but i think the photos are pretty cool. Feel free to share on your site, in case other people are also interested in them!
I found this guy sitting on my car this morning. The specimen shown on BugGuide seems to have wings, but I didn’t see any on mine…
Signature: Stephanie, science nerd
It is always nice to hear about a long time reader who submits images for the first time. Your Brown Marmorated Stink Bug metamorphosis images are quite wonderful, especially because they nicely illustrate how the newly molted insect is much lighter in color, and it will soon darken. The little guy really appears to be struggling.
The Brown Marmorated Stink Bug, Halyomorpha halys, is an invasive, exotic species that was accidentally introduced to North America in Pennsylvania back in the late 1990s, but it has spread quite rapidly according to BugGuide.
We found them in Ohio this summer and last week there was an individual on our window screen in Mount Washington, Los Angeles. Your individual is still a nymph, and it will not be fully winged until its final molt into an adult. More information on this invasive species can be found on the University of California Integrated Pest Management page.
Letter 8 – Brown Marmorated Stink Bug Hatchlings in Poland
Subject: Bug on Betula
January 14, 2014 7:44 am
Hello, I’ve found it on Betula in Poland location. Can You find the anwer for me? I couldn’t find name of this bug out;-(
Squash them immediately. These are hatchlings of the invasive, exotic Brown Marmorated Stink Bug (see BugGuide) and they are native to Asia. They were discovered in Allentown, Pennsylvania in 1998, and in 13 short years, they have spread across half of North America, on both coasts.
Adult Brown Marmorated Stink Bugs seek shelter indoors to hibernate when the weather cools, and that is when they are noticed by homemakers. We expect that they also stow away in luggage, and due to the frequency of people traveling, they are spreading to many parts of the world.
They are expected to become a major agricultural pest in North America because they are such general feeders and they thrive on many cultivated plants. Show them no mercy.
Thank You for Your professional and fast request to my mail. You are welcome to my site www.ochrona.roslin.wroclaw.pl wich is still upgraded.
Letter 9 – Brown Marmorated Stink Bug Nymph
Subject: A True Bug I’ve Never Seen Before
Location: Portland, Oregon
September 20, 2016 6:18 pm
It’s been too many years since I took my college entomology class; are you able to identify unusual-looking bug? It was at rest on a hibiscus shrub and fairly relaxed about having its photo taken. The temperature was 64° and the skies partly cloudy. The location was the outskirts of Portland, Oregon.
Signature: David Hopkins
This is a Brown Marmorated Stink Bug Nymph, Halyomorpha halys, a non-native species that was reported in North America “First collected in 1998 in Allentown, PA, but probably arrived several years earlier” according to BugGuide. In less than 20 years, it has spread across North America and BugGuide reports:
“Native to E. Asia, adventive elsewhere” and “Highly polyphagous, reported on ~300 plant spp. in its native range; feeds mostly on fruit, but also on leaves, stems, petioles, flowers, and seeds. Damage typically confined to fruiting structures.” According to the Minnesota Department of Agriculture:
“Across North America, brown marmorated stink bug has been found in 42 states and two Canadian provinces (Ontario and Quebec). It is causing severe agriculture problems in nine states and nuisance problems in 16 others.”
One of the reasons the Brown Marmorated Stink Bug is considered a nuisance is that they frequently enter homes to hibernate when the weather begins to cool. Needless to say, we have no problem tagging the Brown Marmorated Stink Bug as an Invasive Exotic species. You can compare your individual to this BugGuide image.
Thanks for your very prompt identification! I was familiar with the adult form, but this was the first time I saw the nymph form. You probably get questions about this all the time. In just the last few years it’s become so ubiquitous, that I see it more than any other hemipteran.
Last winter, many tens of them congregated at the bathroom skylight for several weeks and removing them with the vacuum cleaner resulted in a vile stench — they lived up to their name!
Thanks again, Daniel.
Letter 10 – Brown Marmorated Stink Bug nymphs on Tomato plants
Subject: tomato pest ID
Location: San Rafael, CA
August 6, 2017 2:33 pm
Found these critters under my tomato leaves today. It’s been quite hot here but there was a light sprinkle yesterday. Looks like they just hatched? They are eating the leaves but not the fruit yet.
Black, “dirt-like” feces all over the plant and on the ground beneath. Can you please identify them for me so I can figure out how to deal with them? Sorry I could not get a better photo without it getting blurry. Thank you!!
Show them no mercy Lynette,
These are invasive, exotic, Brown Marmorated Stink Bug hatchlings, which you can verify by comparing your image to this Featured Creatures posting where it states: “The brown marmorated stink bug (BMSB), Halyomorpha halys Stål, is a pest that was first officially reported from the western hemisphere in Allentown, Pennsylvania in 2001 (Hoebeke and Carter 2003).
This stink bug may become a major agricultural pest in North America, similar to the southern green stink bug, Nezara viridula (L.). Both species are polyphagous pests of various crops, but in the U.S. it has been primarily reported as a household nuisance and ornamental pest.
However, in eastern Asia where the BMSB is native or indigenous, it is a pest on fruit trees and soybeans.” The holes in the leaves of your tomato plant were caused by something else. Like other Stink Bugs, the Brown Marmorated Stink Bug has a mouth designed to pierce and suck nutritious fluids from plants.
Letter 11 – Brown Marmorated Stink Bug Nymph
Subject: Is this a tick?
Location: Akron, ohio
August 18, 2017 3:23 pm
Found him laying dead upside down underneath the pine tree that has a lot of flying squirrels in it.
This is an immature Brown Marmorated Stink Bug, a common identification request to our site. It is an introduced Invasive Exotic species that has spread across North America in a few years. See this BugGuide image of a nymph for comparison.
Letter 12 – Brown Marmorated Stink Bug Nymphs
Subject: Little Stinkers
Geographic location of the bug: Andover, NJ
Time: 03:56 PM EDT
Your letter to the bugman: Hi Daniel,
Just a share. I found a little cluster of what I believe to be Marmolated Stink Bugs on a hibiscus plant and have been keeping an eye on them. At first they move around together like a little battalion – very cute. Today, however, they molted and started setting out on their own.
All were black except one that is white. I thought that was odd, but read here that sometimes freshly molted nymphs of this species are white, so assume that is what it is.
I am attached a couple of photos showing both color variations as well as one of a nymph inspecting the exuvia, almost as if to say “I can’t believe I used to fit into that thing.”
Hope you are having a great, buggy weekend.
How you want your letter signed: Deborah Bifulco
Based on this BugGuide image, your nymphs are in the second instar phase, meaning they have molted once since hatching. They change and get larger after each molt.
Letter 13 – Brown Marmorated Stink Bug Nymphs
Subject: Beetle from my mulberry tree
Geographic location of the bug: Midwest Missouri
Time: 06:39 PM EDT
Your letter to the bugman: We located a mulberry tree on our property and went to pick the berries. Came across a BUNCH of these little beetles. Looks like the adults are smaller than an eraser on a pencil.
On the underside of several leaves we saw white eggs woven together like honeycomb…one of the leaves had hatched beetles alongside the empty eggs. These babies looked the same as the adults but much smaller, the size of a pinhead.
How you want your letter signed: The Country Bumpkin
Dear Country Bumpkin,
These are NOT Beetles. They are Stink Bug nymphs, but we are not certain of the species. Based on this BugGuide image they might be Brown Marmorated Stink Bug nymphs, an Invasive Exotic species, or they might be Green Stink Bug nymphs, based on this BugGuide image, or they might be a different species entirely. Nymphs can be very difficult to identify with certainty.