Insect Species Spotlight: Brown Marmorated Stink Bug

The Brown Marmorated Stink Bug (BMSB) has become a common pest in North America, causing damage to crops and invading homes during the autumn months.

First identified in the United States in 2001, the BMSB was initially found in Allentown, Pennsylvania. Since then, it has spread to 46 states and four Canadian provinces, with the first recorded sighting in Ohio in 2001. By 2020, it had become a nuisance pest in many areas of Ohio.

Adult BMSBs have a shield shape, measuring approximately 15 mm (5/8 inch) long and 8 mm (3/8 inch) wide. They are mottled with shades of brown and gray on the upper side of the body, and can be distinguished from most other stink bug species by the alternating dark and light bands on the last two segments of their antennae.

The underside of the BMSB's body is white, sometimes with grey or black markings. They have dark, reddish-brown eyes and legs that are brown with faint white banding. Young nymphs are usually half black and half orangish-red when they emerge from eggs. As they grow, they become brown to black, mottled with dull red bands and yellow spots.

The BMSB can cause significant damage to crops such as sweet corn, peaches, apples, and soybeans. In sweet corn, the developing immature kernels are sucked dry by the stink bugs, leaving a condition similar to dented corn but with irregular shrinking of kernels. In peach fruit, damage early in the season results in dark blotches on the fruit surface, sometimes with gummosis and sometimes with cat-facing. Damage in apples appears as a series of discolored irregular depressions in the fruit surface. On soybeans, damage is found on seeds within the pods during pod fill, causing seeds to fail to develop or shrivel.

The BMSB can also be a nuisance when they congregate in large numbers inside and outside of buildings, startling people by flying around, bumping into walls, and landing on lamps, TVs, and computer screens. In extreme cases, hundreds of stink bugs can invade a home. They enter buildings through small openings, mostly around windows, chimneys, and air conditioner units.

The BMSB can be found at high density in crops and buildings in some areas of Ohio, but is often found at low density in crops and buildings in many other areas. It is highly mobile and can switch hosts through the season, moving from plants with early-ripening fruits to those with late-ripening fruits.

As of 2020, there are 175 reported host plants of the BMSB in the United States, including many that are economically important crops. Eggs are pale green, barrel-shaped, and found in clusters of about 28 eggs. The immature stages, called nymphs, are oval-shaped and somewhat tick-like in appearance.

When disturbed, the BMSB can produce a pungent acrid odor. It is important to note that they do not bite people or pets.

In conclusion, the Brown Marmorated Stink Bug is a growing pest in North America, causing damage to crops and invading homes during the autumn months. Understanding the characteristics and habits of the BMSB can help farmers and homeowners take steps to prevent and manage infestations.