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Be on the lookout for brown marmorated stink bug in soybean in southeast Minnesota

by Robert Koch (Extension Entomologist) and Rafael Carlesso Aita (Graduate Student)

The brown marmorated stink bug (BMSB) has been detected in soybean fields in Dakota County, Minnesota for three years in a row. From 2016 to 2018, low numbers of BMSB adults and nymphs were collected in sweep net samples in those fields from mid-August to mid-September. During the pod and seed development stages, soybean is attractive to stink bugs and susceptible to their feeding injury. However, due to the low densities of BMSB observed in Minnesota the last few years, we don’t expect any substantial injury from this pest at this time. However, as populations of BMSB continue to spread and increase, it could become a pest that growers will need to actively manage, which is the situation in some of the eastern states. The purpose of this article is to inform you about the likely presence of low numbers of BMSB in soybean fields in southeast Minnesota. If you find any life stages of BMSB in your crops, please contact Robert Koch (

BMSB looks similar to some native stink bug species; however, it can be distinguished by the light-colored bands on the antennae and the alternating light-dark color pattern located on the edges of the abdomen (Figure 1). In addition, the “marmorated” part of its name comes from the marbled-brown coloration of its body. To aid you in identifying BMSB and some native stink bugs, download the free Midwest Stink Bug Assistant app. 

Figure 1: Adult brown marmorated stink bug (BMSB), with arrows indicating the characteristic light-colored bands on dark antennae and the alternating light-dark patter on the edges of the abdomen.

BMSB is an invasive pest from Asia and was first detected in the U.S. in the mid-1990’s and in Minnesota in 2010. BMSB feeds on a wide range of plant species, including soybean, corn, fruits and vegetables. It feeds by inserting needle-like mouthparts (stylets) into developing soybean pods and seeds. Feeding can cause seed abortion (flat pods) and deformation and discoloration of seed, which can affect yield and quality. In addition, BMSB feeding can result in delayed maturity (stay-green syndrome) of soybean, especially on the edges of fields. See references below for images of injury to soybean. This insect has caused significant yield losses to soybean and other crops in more easterly states. 

Further information about BMSB in soybean can be found in “Stink bugs in Minnesota soybean” and “Identification, Biology, Impacts, and Management of Stink Bugs of Soybean and Corn in the Midwestern United States”. A map of the BMSB detections in Minnesota can be found on the MDA webpage: “BMSB activity in MN”.

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