The brown marmorated stink bug, known to scientists as Halyomorpha halys, is native to Asia. It has been an agricultural pest in China, Japan, and Korea. Scientists think it was accidentally introduced into the United States.
It was first collected in the United States in 1998. It is now found in many parts of the country from Maine to Mississippi and from Oregon to Florida.
The adult brown marmorated stink bug is about ¾” long. Like other stink bugs, its body is nearly as wide as it is long. The adult is mottled brown in color. There are lighter bands on the antennae and dark bands on the front wings.
The immature bug, called a nymph, is yellow and red with red eyes. As it grows, the yellow lightens to off-white.
Like many of the other stink bugs, the brown marmorated is a pest of fruits and vegetables. It has been found feeding on apples, peaches, blackberries, tomatoes, corn, soybeans, lima beans, and green peppers.
Like other stink bugs, this pest pierces the skin of the fruit in order to feed. After feeding, the insect leaves. As the fruit continues to grow, it often develops a scar that looks like the face of a cat.
Besides being an agricultural pest, the brown marmorated stink bug is often a pest in homes. In late summer, the adult bugs gather on homes. The bugs are seeking sheltered places to spend the winter.
The bugs move inside the home through cracks and other openings. They spend the winter hiding inside the walls or in the attic or crawl space. When spring comes, the stink bugs become active. As they begin to move around, some of them emerge into the living space.
Inside the home, the bugs often gather on walls and windows seeking a way out. Homeowners are usually upset to find these bugs inside the home. The size and the unpleasant odor make them very unwelcome.
Homeowners can discourage the brown marmorated stink bug from entering the home by sealing as many entryways as possible. Cracks around doors and windows can be sealed with caulk. Vents in attics and crawl spaces can be protected with screen. Any torn or damaged window screens should also be repaired. Weather-stripping can help seal gaps under exterior doors.
An insecticide barrier can be applied on the foundation and around doors and windows. This can help prevent stink bugs (and other pests) from gathering on the sides of the home. Because rain and sunshine will break down the insecticide, this barrier will have to be re-applied periodically. Pest professionals can select the most effective materials and make the applications.