Recently, I was asked what to do with a stink bug inside the home.
Usually stink bugs are not accidental invaders, but the brown marmorated stink bug is attracted to homes and structures as a protected overwintering site. After finding one in my kitchen, I realized the population of this stink bug is increasing. Two challenges with this pest are keeping them out of the home and reducing the feeding damage they cause on a wide range of crops.
The brown marmorated stink bug was first found in the United States in 1998 in Allentown, Pennsylvania. It was first reported in Kentucky in 2010 and in Daviess County in 2013. Because this stink bug aggregates, the feeding damage on fruits and vegetables is worse than the damage caused by native stinkbug species.
The population in Daviess County is increasing, with the expectation of more damage to fruit, vegetables, and crops and an increase in large numbers of them gathering on homes to find an overwintering site in the fall.
Remove stink bugs found in the home, living or dead, with a vacuum cleaner. When disturbed, they produce a foul odor, so the vacuum cleaner will smell for some time. It is not recommended to use an insecticide indoors.
If large numbers are in the wall voids or attic areas, killing them may possibly lead to carpet beetles feeding on the dead stink bugs, resulting in attacks on woolens, stored dry goods, or other natural products. It is not recommended to treat cracks and crevices where stink bugs may emerge with an insecticide because this will not stop them.
Keeping them out of the home or structure is the best management. Use quality silicone or silicone-latex caulk to seal cracks around windows, doors, siding, utility pipes, behind chimneys, underwood fascia, and any other opening. This can be done throughout spring and summer in preparation for the insect seeking over-wintering sites in September.
How do you identify a brown marmorated stink bug?
Stink bugs, in general, are roundish, shield-backed bugs with five segmented antennae. A brown marmorated stink bug can be recognized as a relatively large and flattened stink bug. Its name comes from the marbled brown and gray colors on its back.
The underside is variable in color but is much lighter than the upper side. It has two wide, light-colored, banded areas on the antennae, distinguishing it from other, similar stink bugs. The abdomen on the brown marmorated stink bug extends past the wings, resulting in light-colored “triangles” visible past the wing edges. When disturbed, the insect will leave a cilantro-like odor.
The brown marmorated stink bug could be confused with other brown stinks bugs common throughout the state and found on many of the same fruit, vegetable and fields crops.
We have at least three pest species of brown stink bugs in Kentucky. Two of the larger species of brown stink bugs can have the last segment and a half of the antennae darkened.
However, they don’t have the light-colored bands on the antennae. Brown stink bugs have a series of fine teeth on the leading edges of the thorax. They do not attempt to enter homes in large numbers.
One of our beneficial stink bugs, the spined soldier bug, can also be mistaken for the brown marmorated stink bug. It feeds on a wide variety of vegetable and field crop pests. The spined soldier bug is somewhat smaller, with a similar marbled appearance but without the light bands on the antennae.
The spined soldier bug can also be distinguished from other stink bugs by a dark marking on the membranous part of the front wings. When they overlap there is a brown mark near the tip of the wings.
Like other species of stink bugs, the nymphs and adults of the brown marmorated stink bug use their piercing-sucking mouthparts to feed on leaves and fruits of plants. Their feeding results in small discolored or necrotic areas on leaves. Damage to fruits includes water-soaked legions or cat-facing ranging from mild to severe. This stink bug feeds on over 100 plant species and is highly mobile.
Stink bug populations start to build in May and seem to peak in late July to early August. To manage them in the garden, covering plants with fine netting that is 1/6” or smaller blocks the pest.
However, netting may not be practical with crops that need pollinators to set fruits. When pest populations are low, routinely hand picking in the morning when they are sluggish and dropping them in a bucket of soapy water may work for small numbers of plants.
In the home garden, the last resort is chemical control. Remember that the product must be labeled for use on the specific crop. Check the waiting days until harvest after applying the product, and protect pollinators by applying the product in the evening after squash and cucumber flowers are closed or avoid applying it while the plant is in bloom.
Through scientific studies, some of the pyrethroid insecticides with the following active ingredients have shown to be effective include: bifenthrin, zeta-cypermethrin, and cyfluthrin. Malathion, which is an organophosphate, can be effective, too.
For more information about the brown marmorated stink bug, contact the Daviess County Cooperative Extension Service at 270-685-8480.
In order to identify the brown marmorated stink bug, bring it to the Daviess County Cooperative Extension Service Office. Pest-proofing the home is the best way to keep them out.
Annette Meyer Heisdorffer is the Daviess County extension agent for horticulture. Her column runs weekly on the Home & Garden page in Lifestyle. Email her at email@example.com.