Brown Marmorated Stink Bug

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What are they?

The brown marmorated stink bug (BMSB) is a 0.5- by 0.625-inch shield-shaped insect that uses its piercing mouthparts to suck plant juices from fruits, seed pods and nuts on a wide variety of wild and cultivated plants. It was accidentally brought to North America from Asia sometime before 1996 and was first detected in Michigan in 2010. Also known by its scientific name, Halyomorpha halys, both BMSB adults and nymphs – the immature stages of the bug – feed on a number of important fruit, vegetable and ornamental crops. Where it has been established for some time, it is now a major pest for growers of susceptible crops. As of August 2020, it has been found in all Michigan counties and is well established in the southern part of the Lower Peninsula.

For HOME or STRUCTURAL concerns

What are they doing in my home?

At the end of the summer and into the fall, you may start to find brown marmorated stink bugs appearing in homes and other buildings. They are looking for a protected place to spend the winter. They will leave your house again in the spring – if they can find their way back out – to look for plants to feed on and lay their eggs outside.

They are NOT nesting, laying eggs or feeding on anything or anyone in your house. These are plant-feeding insects with straw-like mouthparts for drinking plant juices – they are harmless to humans and pets.

What can I do about it?

Try not to panic.
Look for gaps around window air conditioners or holes in window screens and block them off – these are easy access points for brown marmorated stink bugs to enter homes.
The easiest, non-toxic way to dispose of them is with a couple inches of soapy water in a bucket – the soap prevents them from escaping the water. Sweep them into the bucket and they will drown in the soapy water, which you can then dump outside. Or you can do the same with a Shop-Vac – add the soapy water to the canister before vacuuming them up with the Shop-Vac.

For more tips on managing them in your home, see our tip sheet on stink bug identification and management in homes or read this article, "Managing brown marmorated stink bugs in homes."

For GROWER concerns

What crops are affected?

Brown marmorated stink bug can feed on more than 300 different plants including many agricultural and ornamental crops – almost anything that produces fruit, pods, or nuts. Feeding damage has been recorded in high-value specialty crops, in particular apples, pears, peaches and other stone fruit, fruiting vegetables such as tomatoes, sweet peppers, squash, pumpkins, sweet corn, and green beans, and field crops such as soybeans. They can also become a contaminant during juice or winemaking in grapes. For more information on susceptible crops, visit the Stop BMSB website.

How do I monitor and manage them in my crop?

Brown marmorated stink bugs move around during the season among different habitats, coming out of woodlots and manmade structures in the spring to find host plants. There are exotic tree species common in Michigan woodlands and especially in more urban areas that are favored in the early season, especially Tree of Heaven. Later they will move into crop habitats, especially soybean fields, vineyards, and orchards. Their movement appears to coincide with the development and maturity of seed pods and fruit in these crops.

In general, you are most likely to find the pest in the edges of a crop planting. Sweep netting will work in field crops to monitor for the pest. In orchards and vineyards, beating limbs or vines over trays can help determine whether they are present. There are also commercial lures that can be paired with various traps to attract them for recording their number from week to week. Traps are best used between two habitats, like between a woodland and the crop of concern. Thresholds are still being developed in many crops that use these traps.

For more information about damage assessment and management strategies in fruit:

Michigan Fruit Management Guide, MSU Extension bulletin E0154
Managing Brown Marmorated Stink Bug in Michigan Orchards by MSU (last updated August 2020)
Look-a-like late season apple damage by bitter pit, brown marmorated stink bugs or apple maggot by MSU
Integrated Pest Management for Brown Marmorated Stink Bug in Vineyards by Stop BMSB
Integrated Pest Management for Brown Marmorated Stink Bug in Small Fruit by Stop BMSB

For more information about management in vegetable crops:

Midwest Vegetable Production Guide for Commercial Growers, MSU Extension bulletin E0312
Integrated Pest Management for Brown Marmorated Stink Bug in Vegetables by Stop BMSB

2020 trap line reports

MSU Extension runs a trap line in the major fruit and vegetable growing regions in the Lower Peninsula of Michigan, monitoring between 60-80 sites each week during the season. Look for updates in regional fruit reports from MSU Extension or talk with your local Extension educator for more information on BMSB populations in your area.

What to do if you are not sure whether you have a BMSB?

Place it in a dry box with tissue paper or in white vinegar and mail or drop off to:
Howard Russell
Diagnostic Services
578 Wilson Rd., Room 116
East Lansing, MI 48824

Be sure to include with the specimen the location where you found the insect and your name and contact information (email or phone if no email). See additional tips for submitting insects for identification to MSU Diagnostic Services.