More and more people in the U.S. are having to deal with the brown marmorated stink bug (BMSB), Halyomorpha halys. It is truly a nuisance bug: it is an agricultural pest; it is invasive (meaning that it is undesirably and harmfully moving into different areas); it has few natural enemies; and it often tries to enter people’s homes. Dealing with these bugs has not been easy, as when they are crushed or become irritated, the aptly named stink bug emits a pungent odor from scent glands on its abdomen. Therefore, many people would rather not kill them and then have to deal with the smell. Fortunately, they do not bite people or animals.

The brown marmorated stink bug is native to China, Taiwan, Japan, and Korea but was accidentally introduced into the U.S., perhaps arriving in a shipping container. First noted in 1998 near Allentown, PA, it has since spread throughout the mid-Atlantic region, across the United States, and into Canada: It continues to expand its range and impact.

BMSB becomes a nuisance pest both indoors and out when it is attracted to the outside of houses on warm fall days in search of protected, overwintering sites. It also appears during warmer sunny periods throughout the winter, and again as it emerges in the spring.

Stink bugs tend to collect in large clusters. When a BMSB finds a site that is suitable for overwintering, it releases a chemical called an aggregation pheromone, a scent that attracts other brown marmorated stink bugs to the area. The aggregation pheromone is, by the way, not the same chemical that causes them to stink.

Managing this pest species is challenging. Researchers are working to find the safest and most effective methods to control BMSB. Chemical pesticides are dangerous in many ways and have ongoing negative effects. Some farmers have sprayed aggressively to keep BMSB in check, despite uncertainty about which products effectively control it. But broad-spectrum sprays also kill beneficial insects that help to control pest populations, presenting a setback for growers who use integrated pest management to promote nature’s own checks and balances on their farms. In addition, the risk of pest resistance increases with greater use of chemical products.