Brown marmorated stink bug
Halyomorpha halys
Nina Abesadze · Lagodekhi Georgia field photo
Key facts in one look
- Size
- 12-17 mm
- Group
- Insect
- Status in Georgia
- Confirmed invasive pest
- Identification
- Marbled shield body and pale-banded antennae
- Main issue
- Crop damage and entry into buildings
- Family
- Pentatomidae
The brown marmorated stink bug (Halyomorpha halys) is an introduced pest in Georgia that damaged the hazelnut crop in 2016. It feeds on plant sap and is of particular concern in gardens, hazelnut groves and orchards. An adult is about 12–17 mm long. Its body is broad and flattened like a shield, brown and mottled like marble. White bands help you identify it: they show on the antennae, the legs and the side edge of the abdomen. It was first recorded in 2016, in Khobi Municipality and Pitsunda. In 2017, control efforts focused mainly on the parts of Samegrelo, Guria, Samtredia and Gali where the bug had spread. By the end of that year it had also appeared in eastern Georgia, so it is no longer a pest of western Georgia alone. Today there are records from all 12 regions, though only isolated cases are known so far in 4 of them, and its distribution is assessed as restricted. In official Georgian sources it is also called the Asian stink bug.
Identification
Brown marmorated stink bug: how to identify it
The brown marmorated stink bug has a broad body, flat like a shield, brown and marbled. Its antennae carry white bands, and light and dark spots or stripes alternate along the sides of its abdomen. You can recognize it by these features if you look at the body shape, the antennae and the sides of the abdomen together.
Seen from above, an adult looks like a shield. Its body is broad and slightly flattened, and it is about 12–17 mm in size.
You cannot identify it by colour alone: it sometimes looks greyer or dark brown. More reliable signs are the white bands on its antennae and the alternating light and dark patches along the outer edge of its belly.
Its legs also show light-colored stripes, and the corners of its shoulders have no sharp spines. So just seeing a brown stink bug does not yet mean it is this species.
Young bugs are smaller than adults, and their color changes as they grow. Newly hatched ones may be reddish; later they develop dark and whitish-brown coloring.
This shield bug can be confused with other shield bugs found in Georgia. To tell exactly which one it is, take a clear photo from above that shows its antennae, the sides of its abdomen and its body shape.
Often confused with
Comparison
How is it different from other stink bugs?
Several native and introduced stink bugs can look brown at first glance. For Halyomorpha halys, identification is strongest when the same photo shows the pale-banded antennae, alternating abdominal edge, rounded shoulder corners, and pale-banded legs.
Brown colour or an unpleasant smell alone is not enough for identification.
- 1Two pale antennal bands
- 2Pale-dark abdomen edge
- 3Rounded shoulders
- 4Pale bands on the legs
Damage and control
What damage does brown marmorated stink bug cause?
The damage comes from feeding. Adults and nymphs pierce young shoots, leaves, fruit, nuts, or seeds and suck plant sap. Important host crops in Georgia include hazelnut, pome and stone fruit, berries, vegetables, sunflower, and maize.
| Crop | What is damaged | How the damage looks |
|---|---|---|
| Hazelnut | Young shell and kernel contents are pierced and drained during nut development. | Thinned or shrivelled kernel contents, corky or rotting spots, lower market quality. |
| Peach, nectarine, apple, pear | Fruit tissue is pierced while the insect feeds on sap. | Depressed, discoloured, or corky feeding marks and reduced fruit quality. |
| Tomato, pepper, other vegetables | Soft fruit and shoots can be fed on by nymphs and adults. | Pale or sunken feeding spots and fruit that loses quality before harvest. |
| Berries, sunflower, maize | Seeds, fruit, and other soft plant parts may be attacked. | Sap-feeding injury, quality loss, and local crop damage when numbers are high. |
In a strong outbreak, the loss may reach up to 70% of crop value. That is an outbreak-risk figure, not a prediction for every garden or field.
What should you do if it enters the house?
Adults often enter buildings in autumn because they are looking for dry overwintering shelters. Indoors, the goal is removal and exclusion: avoid crushing them, remove them mechanically, and close entry points.
Do not crush it
Crushing releases a stronger odour and can leave smell on surfaces.
Use soapy water
Collect individuals with paper or a container and place them in soapy water.
Vacuum carefully
A vacuum can work for many insects if the container or bag can be cleaned afterward.
Block entry points
Seal window and door gaps, cracks, attic openings, and damaged screens before autumn aggregations begin.
Be careful with chemicals
Use pesticides only according to the label, registration, and official agricultural guidance.
In Georgia, the brown marmorated stink bug is found mainly on farmland and in settled areas. These include hazelnut and fruit orchards, vegetable plots, yards and garden edges, as well as bushes and trees with plants it feeds on. It is an introduced pest, not a native species whose protection matters in forests or steppes. There are records from all 12 regions of Georgia. In 4 of them, however, only individual cases are known. Photos taken on site document records from Chiatura, Kutaisi, Lagodekhi, Kvareli, Akhmeta, Mtskheta and Old Tbilisi.
The map for Halyomorpha halys combines Reptiles.ge editorial photo records with public iNaturalist observations. Region-level literature evidence and individual occurrence records are separate layers, and record counts reflect observation effort rather than population density.
Data: Reptiles.ge + iNaturalist · Methodology
- Field observation
- Several records in one spot
- Photo record
- Source-confirmed region
The brown marmorated stink bug feeds on a very wide range of plants and damages them. Its food plants include hazelnuts, pome and stone fruit trees, berry plants, vegetables, sunflowers and corn. Peaches, nectarines, apples, pears, raspberries, tomatoes and peppers are among them too. Both adults and young bugs pierce leaves, shoots, fruit or seeds with their mouthparts and suck out the juices. Feeding often leaves sunken, discolored or cork-like damage on fruit. This harm falls on farming; it does not mean the bug attacks or bites people.
In Georgia, these bugs start feeding in spring, in late April or May, and keep feeding until late autumn. They lay their eggs in groups on the undersides of leaves. Young bugs hatch a few days later and pass through five stages of development before becoming adults. Observations in western Georgia recorded two complete generations. This finding applies to western Georgia and does not mean the bugs develop on exactly the same schedule everywhere in the country. In autumn, adult bugs look for dry, sheltered places to spend the winter. That is why they may get into homes and attics, gaps around doors and windows, and other cracks. They may also shelter in tree hollows and fallen leaves. If you trap or crush one, it releases a strong smell.
In the fight against the brown marmorated stink bug, the key is to keep track of its spread and act accordingly. To do this, the state monitors the insect, sets traps, plans measures based on where it has spread and keeps the public informed. In your own garden, the first step is to check it regularly. You can read more about where the insect occurs in Georgia, how it lives and how it is controlled in this overview. In gardens and hazelnut groves, choose your measures based on whether the bug is really there and what stage of development it has reached. For chemical treatment, official recommendations pay special attention to the stage when the bug is still young and has not yet become an adult. Use only registered products and follow the label instructions. Wear protective equipment and follow official agricultural advice.
Yes. This pest has been confirmed in Georgia. It was first recorded in 2016, in Khobi Municipality and Pitsunda. By the end of 2017, it had also appeared in eastern Georgia, so it is no longer a pest of the west alone.
There are records of the brown marmorated stink bug from all 12 regions of Georgia. In 4 of them, though, only a few cases are known so far. Photos taken on site document records from Chiatura, Kutaisi, Lagodekhi, Kvareli, Akhmeta, Mtskheta and Old Tbilisi.
It has a shield-shaped body, 12–17 mm in size, with a brown marbled pattern. There are white bands on the antennae, and light and dark spots alternate along the sides of the abdomen. Brown colouring alone will not tell you it is this species. So look for all of these features together.
No. The Asian stink bug does not bite people or pets. Nor does it pass diseases to people or animals.
In autumn, adult stink bugs look for dry, sheltered places to spend the winter. So they may get into attics, gaps around doors and windows, or other cracks.
In Georgia, hazelnuts suffered particularly heavy damage. The pest also damages fruit trees, berry plants, vegetables, corn and sunflowers.
Do not crush the bugs. Remove them without touching them directly and drop them into soapy water. You can also collect them with a vacuum cleaner. Use pest control products only as directed on the label and in line with official safety rules.
References
What this profile is based on
Species profiles are compiled from peer-reviewed literature and established biodiversity databases, and are reviewed as new taxonomic and conservation data become available.
Prepared by the Reptiles.ge editorial team from the sources listed here.
