Stink Bugs

The brown marmorated stink bug (BMSB) is considered an invasive species, or a pest of foreign origin, as it was introduced to the United States from Eastern Asia in the mid-1990s. It is also referred to as the yellow-brown or East Asian stink bug. The bug was first collected in the United States in Allentown, PA in the fall of 1996, but apparently not recognized or identified until September 2001. It quickly spread east to New Jersey, then Virginia by 2004, and now southward to the North Carolina border. Today, brown marmorated stink bugs are most prevalent in the mid-Atlanta region, but they have been identified in 44 states and the District of Columbia. The bug’s native range includes China, Japan, Korea and Taiwan.

The stink bug earned its name from its tendency to release an odor when disturbed or when crushed. Many other insects have these same characteristics, including some species of ants, beetles and other bugs. 

Stink bugs are described in several different ways. They are characterized as both “large, oval-shaped insects” and “shield-shaped insects.” Adult stink bugs can reach almost 2 cm in length. They are nearly as wide as they are long. Their legs extend from the sides, so this makes the adult bugs appear even larger. The brown marmorated stink bug is a brownish stink bug. It has lighter bands on the antennae and darker bands on the wings.

Adult stink bugs are good fliers and fold their wings on top of their body when they land. Nymphs do not have fully developed wings. The wings appear when the nymph becomes an adult. Fully developed wings are a way to identify adult stink bugs.

Immature stink bugs, called nymphs, are very tiny when they hatch from their eggs. Nymphs of the brown marmorated stink bug are yellow and red. As they grow, the yellow fades to white. They have bright red eyes during the nymph stage of their life cycle. The nymphs molt or shed their skin five times. Each time a stink bug nymph molts, it becomes larger. By the last molt, the nymphs are almost as large as adult stink bugs.