Brown Marmorated Stinkbug in Corn and Soybean

The brown marmorated stinkbug (Halyomorpha halys) (BMSB) is a pest that was introduced into the US about 10 years ago. Like many recent invaders, BMSB is native to Asia and likely hitchhiked to North America in shipping containers. The BMSB feeds on the fruits and seed pods of a wide range of plants including corn and soybeans.


Like other stink bugs, BMSB are shield-shaped and have long piercing-sucking mouthparts. They often release an odor when crushed. The upper side of the body on adults is mottled shades of brown and gray and is covered with dense puncture marks. The underside of the body is white, sometimes with gray or black markings. They have dark red eyes and the legs are brown with faint white banding. Broad light and dark bands on the last two antennal segments distinguish BMSB from other stink bugs. The immature stages, called nymphs, are oval-shaped. Young nymphs are yellowish brown, mottled with black and red. Older nymphs are darker with light bands on dark legs and antennae, similar to the adults.

BMSB Adult 

BMSB Nymph 

Young nymph stage of BMSB 


BMSB overwinter as adults in protected areas, including buildings. In the spring, adults mate and females lay egg clusters on host plants. There are five nymphal instars that feed on host plants during the summer. The new adults also feed, then seek overwintering sites in the fall.


Brown marmorated stink bug is very mobile. Both nymphs and adults feed on corn and soybean plants, making it potentially damaging to crops.

BMSB is a true bug, feeding on plant juices with a piercing sucking mouthpart and injecting saliva as it feeds. This feeding can puncture and scar plant tissue, resulting in distortion of the growing tissue around the feeding scar. Damage may not be seen until husks and pods are opened in corn and soybean. In corn, BMSB feeds through the husk and damages the developing ear, resulting in unfilled or shrunken kernels. In soybean, BMSB feeds through the developing pod, resulting in aborted or shrunken seeds. Soybean fields may be damaged along field borders near tree lines2. Damage can result in a ‘green-stem’ phenomenon along the borders where plants fail to naturally senesce as they try to compensate for insect damage. BMSB that are crushed in the chopping of silage and fed to dairy cattle may cause an off flavor in milk (a cilantro-like flavor).

Brown marmorated stink bug damage 

Green-stem phenomenon on soybeans 


The BMSB is very mobile and expected to be problematic again in 2011 in corn and soybean fields. Suspected insects or damage from BMSB can be brought to local county extension offices for identification and reporting. Presently, entomologists are still developing thresholds for BMSB in agricultural crops. Many insecticides, including pyrethroids, are effective against BMSB; however, spray equipment needs to be adjusted to allow for adequate coverage of the product. Damage to crops may be most severe near tree lines, and field perimeter treatments may be used to temporarily stop a BMSB invasion. Such treatments likely will limit the insect for a short time as BMSB can move in and out of fields as well as move farther into the field. While control options are currently limited, and there is some evidence of resistance research by various extension services is continuing1.