This bug stinks: the brown marmorated stink bug

By Joan Allen - UConn Home & Garden Education Center
Featured Article - posted Tue., May. 7, 2013
- Contributed Photo

Many people have memories of stink bugs from when they were kids, impressing their friends with the information that these amazing bugs could produce a horrible smell if squashed or threatened. This odor is produced by chemicals called aldehydes that are released from glands on the thorax to deter predators. There are a number of native stink bugs, but there is a recent arrival to the United States from Asia called the brown marmorated stink bug (BMSB). Its scientific name is Halyomorpha halys and it belongs to the family Pentatomidae and the order Hemiptera. Stink bugs are true bugs, meaning they have piercing and sucking mouth parts. It probably found its way to the U.S. by hitching a ride on packing material on a cargo ship.

BMSB overwinters as an adult. In April, the adults begin feeding on leaf tissue and eggs are laid from May through August on the undersides of leaves. Eggs are light yellow to yellow-red with minute spines, and are laid in clusters of 20-30. The eggs hatch into small black and red nymphs that go through five molts before reaching the adult stage. The adults are shield shaped and 14-17mm in length. There are some native stink bugs that look similar to the BMSB. Distinctive markings of BMSB include alternating light and dark bands on the exposed abdominal edges and on the antennae of the adults. There is probably one generation per year, but there may be the potential for two in seasons with a warm spring and summer.

The BMSB was first confirmed in the United States in Allentown, Penn., in September 1998 and has since been confirmed in many mid-Atlantic and other states, including Connecticut. The first report in Connecticut was in New Haven County in 2008. This bug is an important agricultural pest and a nuisance pest. Both the immature nymph stages and the adults feed on plant material including both leaves and fruits. The host range is broad, including tree fruit, ornamentals, vegetables, weeds and brambles. It has already caused serious damage to fruit, vegetable and other farm crops in the mid-Atlantic states and is likely to continue expanding its U.S. range into the northeast and other areas. Feeding injury on fruits includes small dead spots, darkened, water-soaked spots and ‘cat-facing’, a distortion of the fruit. Orchards were surveyed for this pest from 2003 to 2006 with no finds. So far, all specimens found in the state have been found indoors (records of Connecticut Agricultural Experiment Station). Surveys at fruit and vegetable farms will continue this year using traps to monitor for the BMSB’s presence.

Like the Asian ladybeetle and boxelder bugs, this insect can also be a nuisance pest when it enters structures looking for protected overwintering sites. The overwintering adults may find their way indoors during mild winter weather or in the spring, most actively in mid-April to mid-May. They do not lay eggs and reproduce indoors and do not cause any human or animal health problems. If they do find their way indoors, the best method of removal is to use a vacuum cleaner, although the vacuum may retain the stink bug’s characteristic odor for a while. Insecticides are not recommended. Treatment with insecticidal dusts may kill many of the stink bugs, but the dead stink bugs (in wall voids, etc.) may attract carpet beetles that feed on any animal material. Foggers will kill some stink bugs as well, but the effectiveness is short-lived and the chemical will dissipate as soon as the space is aerated. Prevent insects from entering the home by sealing all cracks and crevices that allows them access. These include cracks around door and window trim, light and ceiling fan units and along baseboard trim. Most of the specimens found in Connecticut so far have been found inside of houses or condominiums.

If you think you have seen BMSB, either indoors or out, Connecticut is still monitoring the occurrence of this pest. Please contact your county extension office or the UConn Home & Garden Education Center for an identification. Digital photos of specimens can be sent to for identification. Please include the name of your town or county, where the insect(s) were found, and the approximate number observed. The toll free phone number for the Home & Garden Education Center is 877-486-6271 for identification or additional information.

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