Brown Marmorated Stink Bug


The brown marmorated stink bug (BMSB), Halyomorpha halys, is a non-native, invasive insect recently discovered in North America. It is a pest of fruits, vegetables, and farm crops. It becomes a nuisance pest when it invades structures to find a place to overwinter.

BMSB is a native insect of China, South Korea, Japan, and Taiwan. The first BMSBs in the United States were found in Allentown, Pa., in 1990s. It is suspected that they were on fruit shipped in packing crates from Asia. BMSB was detected in West Virginia in 2004. BSMB is now found in at least 26 states from Maine to California. It is expected to expand its range across North America.


BMSB_Adult Adults are about -inch long and shaped like a “shield.” They have varying shades of brown on both the upper and lower body surfaces. They differ from other stink bugs in that they have lighter bands on the antennae and darker bands on the membranous, overlapping part at the rear of the front pair of wings. The head and pronotum have small round depressions that resemble coppery or metallic-bluish colored punctures. Stink bugs get their name from the scent glands located on the dorsal surface of the abdomen and the underside of the thorax.

BMSBs have small, elliptical-shaped eggs that are light yellow to yellow-red with tiny spines. They attach in rows on the underside of leaves in masses of 20 to 30 eggs that may be shield-shaped.

BMSB_first instars There are five immature stages known as nymphal instars. They range in length from 1/8 inch at the first stage to inch at the fifth stage. They have deep red eyes and abdomens that are yellowish red in the first stage, progressing to off-white with reddish spots in the fifth stage. Bumps are found before each of the abdominal scent glands on the top surface. The legs, head, and thorax are black. Spines are found on the femur, in front of each eye, and on the lateral margins of the thorax.


The insect feeds on a variety of fruits, vegetables, and farm crops. When BMSB feeds on produce, it causes blemishes known as “cat facing, ” which makes it unappealing and unmarketable as a fresh product. Significant losses have occurred for farmers whose peach and apple orchards have been hit by BMSB. Refer to picture of damage on fruit.

Although BMSBs do not pose a health threat to humans, once they enter a home they can cause alarm while flying around and emitting a strong odor when they are crushed.

More Resources

Related Links

Brown Marmorated Stinkbug
Regional Pest Alert--Brown Marmorated Stink Bug PDF
USDA Damage Report PDF
Protect your home from winter pests