The devastating potential of this insect has triggered a flurry of research activity by state and federal agricultural researchers.

USDA-ARS researchers in West Virginia say there are two full generations of BMSB beginning with the previous year’s overwintered adults in the spring. These become active, move into orchards and start to feed and mate. Egg masses are laid with nymphs hatching soon afterwards. The nymphs feed voraciously while undergoing five nymphal stages before developing into adults, ending the first cycle of the year. By September the second generation of adults is present and may begin to leave the orchard to overwinter. Warm spring and summer conditions could permit the development of two or three generations. However, in parts of sub-tropical China, records indicate from four to possibly six generations per year.

Mass migrations of adults flood into urban areas, including homes, looking for a warm place to overwinter causing public outcry. Although harmless to people, their unpleasant odor emitted when disturbed make them equally unpopular with urbanites.

Adults are approximately 17 mm long (25 mm = 1 inch) and have shades of brown on both the upper and lower body surfaces. They are the typical “shield” shape of other stink bugs, almost as wide as they are long. To distinguish them from other stink bugs, look for lighter bands on the antennae and darker bands on the membranous, overlapping part at the rear of the front pair of wings. They have patches of coppery or bluish-metallic colored puntures (small rounded depressions) on the head and pronotum. The name “stink bug” refers to the scent glands located on the dorsal surface of the abdomen and the underside of the thorax.

The eggs are elliptical (1.6 x 1.3 mm), light yellow to yellow-red with minute spines forming fine lines. They are attached, side-by-side, to the underside of leaves in masses of 20 to 30 eggs.

There are five nymphal instars. They range in size from the first instar at 2.4 mm to the fifth instar that is 12 mm in length. The eyes are a deep red. The abdomen is a yellowish red in the first instar and progresses to off-white with reddish spots in the fifth instar. Protuberances are found before each of the abdominal scent glands on the dorsal surface. The legs, head and thorax are black. Spines are located on the femur, before each eye, and several on the lateral margins of the thorax.

According to Oregon entomologists, there are several native stinkbugs that closely resemble BMSB. Rough stink bugs, and their relatives, are often encountered. Adult rough stink bugs can be easily distinguished from adult BMSB. Rough stink bugs have distinct teeth on the edges of the thorax, or “shoulders,” just behind the head and all the antennal segments are one color. BMSB have no teeth on the edges of the thorax and the last two antennal segments have white bands.