Brown Marmorated Stinkbug in the Home Garden

Jessica Cole, Extension Associate, and Ric Bessin,Extension Specialist


Brown marmorated stink bug (BMSB), Halyomorpha halys, is a new invasive species from Asia. First detected in Kentucky in 2010 it can now be found in multiple eastern and central Kentucky counties. BMSB is very mobile in the landscape and a serious pest that has a wide range of host plants, including significant agricultural and horticultural crops. BMSB aggregates in large numbers when feeding and can do significant damage to high­ value crops. BMSB generally attacks the fruiting parts of plants, but it will also feed on other succulent parts, and the nymphs feed on leaves. In the fall the BMSB becomes a nuisance pest (like the Asian lady beetle) by migrating to homes and other buildings to overwinter. The last two weeks of September through the first two weeks of October is when high numbers of BMSB start coming into homes. When disturbed the BMSB will release a pungent odor that smells like cilantro.


BMSB have the characteristic "shield" shape like all stink bugs. Adult BMSB are 14-17mm (5/8 inch) long, which makes them one of the larger stink bugs in Kentucky. They are a mottled brownish-grey color and have smooth shoulder margins without any toothed edges.

BMSB has two distinct white bands on its otherwise dark antennae. The edge of the abdomen beyond the wings also has this alternating dark and light banding. The underside of the BMSB is white with some dark markings.


From June to August females lay clusters of 25-30 light green barrel-shaped eggs on the undersides of leaves. Nymphs go through five different instars (stages) to reach adulthood while feeding throughout the summer and fall.

The nymphs are brightly colored red and black that look like a smaller version of the adult stink bug. Older nymphs are a darker color with banding on their antenna and legs, similar to the adults. Based on published growth models, there should be one to two generations per year depending on the location in the state the summer temperatures.


BMSB is notable for having a wide range of hosts, over 100 plant species, including vegetable crops, grain crops, fruit crops and ornamental crops. Like other species of stink bugs both nymphs and adults use their piercing-sucking mouth parts to feed on leaf and fruit tissue. BMSB feeding can result in small discolored or necrotic areas on leaves and various types of damage to fruit. Fruit damage may include water-soaked legions or cat-facing ranging from mild to severe. When feeding the BMSB aggregate in large numbers resulting more damage than our native stinkbug species.

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      For more information, call Shad Baker, Letcher County CEA for Agriculture and Natural Resources at 633-2362,

634-7799 or email at

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