The brown marmorated stink bug (BMSB), Halyomorpha halys, has been confirmed in Billings (on January 26, 2021 from a household near downtown Billings-found alive inside the home). It was just recently confirmed from inside the car of a homeowner in Kalispell on May 5, 2021 (either flew into the car at Herron Park or at Flathead Lake).

Close-up photo of a speckled brown diamond-shaped insect

Adult brown marmorated stink bug.  Photo by Lauren Kerzicnik, MSU. Large image (850KB)

The brown marmorated stink bug was introduced from Asia and is now established in 46 states (Montana is the 47th state but not sure if it is yet established) and 4 Canadian provinces. It attacks over 170 different plant species. This is a pest that was expected to arrive in Montana. Its potential impact on crops, specialty crops, backyard gardens, and as a fall home invader in Montana are unknown.


Brown marmorated stink bugs have stylets, which pierce into the fruit, pods, buds, leaves, and stems of several plants.

Preferred Hosts

Yard and garden: Some preferred hosts in the yard and garden include catalpa, sunflower, crab apple, apple, cherry and other Prunus species.

Crops: Corn is a favored host of BMSB.

Specialty Crops: Specialty crops at high risk to BMSB damage include apples, pears (Asian and European), grapes, peaches, sweet corn, peppers, Swiss chard, and tomatoes.

What We Know About BMSB

  • Wide host range
  • Damaging pest of apples, grapes, cherries, and several other Prunus spp.
  • Harmless to humans
  • Invades homes in the fall (nuisance pest)
  • It is a serious pest of economic importance for tree fruits in the mid-Atlantic states and has caused more than $37 million worth of damage (report as of 2010).
  • Its detection in other states poses problems ranging from a nuisance pest to a severe agricultural pest.

What We Don’t Yet Know About BMSB in Montana

  • If it is established in Montana (if reproductive populations exist in Billings and other areas of the state)
  • What hosts it might impact and whether it will be a pest of economic importance for crops and specialty crops

Monitoring and Management

  • Several cooperating state and federal agencies have been monitoring for BMSB for several years in Montana.
  • Monitoring efforts will continue with a focus in the Billings area.
  • Please send suspected specimens and/or detailed photos to your local extension agent or samples can be submitted to the Schutter Diagnostic Lab and further directions can be found at the Schutter Diagnostic Lab website.  Please note: there are several look-alike insects (see the Stop BMSB page).
  • Detailed management information and other information about the pest can be found at the website.

Further Information

Many thanks to Bruce and Amy Morey for collecting the specimen (and initial diagnosis) and Amy Grandpre (Yellowstone County Extension, MSU) for sending the specimen to the Schutter Diagnostic Lab.  To learn more about the brown marmorated stinkbug, contact Dr. Lauren Kerzicnik at the Schutter Diagnostic Lab.

The Montana State University Extension Service is an ADA/EO/AA/Veteran’s Preference Employer and Provider of Educational Outreach.

This fact sheet is also available in a Printable PDF format (650KB).  May 2021


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