Brown marmorated stink bug spreading across U.S.

Initially reported around Allentown, Pennsylvania, the brown marmorated stink bug (BMSB), or Halyomorpha halys (Stal), has become a crop pest and household nuisance throughout Maryland and adjacent states. Native to Asia, BMSB is thought to have arrived through shipping material and is now established throughout the Mid‐Atlantic and parts of the West Coast. This invasive species is an excellent hitchhiker and has entered over half of the contiguous United States. Life cycle As BMSB is a relatively new pest, we are still learning about the pest’s life cycle. Entomologists have reported one generation per year in Pennsylvania and New Jersey, but West Virginia researchers have seen 2 generations a year (Nielsen and Hamilton 2010, Holtz and Kamminga 2010). A warmer climate speeds the BMSB development process, and life stage development depends on daylight and temperatures. In BMSB’s native habitat, research suggests 4‐6 generations per year. The following life history facts are based on the BMSB life history in Pennsylvania. Stay tuned to University of Maryland Extension updates and the IPM Pest Alert which go out every Friday from March through October. We will post additional life cycle information as the research continues. The eggs are light green to almost white in color and are laid in clusters of 25‐30. Eggs are often on the underside of leaves and can be found from May through August. Over time, a female BMSB can deposit over 200 elliptical‐shaped eggs. Monitor for these eggs by examining the undersides of foliage. The BMSB nymph has five instars, or juvenile development stages. The nymph ranges from 2.4 mm to 12 mm in length. Nymphs are characterized by dark reddish eyes and a yellowish‐red abdomen with black striping. The antennae of the nymphs are similar to adults—black with white banding. Pennsylvania’s nymph population peaks in July and August, while adult populations are highest in September. BMSB overwinters as an immature adult in houses and other structures. They are typically inactive during the winter months, but indoor heating has kept many stink bugs moving this year.