Increased international trade and the relative ease of world-wide travel allows insects to move from their native home to the United States. A new stink bug, the brown marmorated stink bug, Halyomorpha halys (Stal), was found in Pennsylvania in 2001. It was accidentally introduced into the Allentown, PA, area, possibly in shipping containers from Asia. The brown marmorated stink bug is known to occur in six eastern Pennsylvania counties and two adjacent New Jersey counties.
The brown marmorated stink bug is native to Japan, Korea, China, and Taiwan. It is both a direct pest and an indirect pest. In its native range, it feeds on a wide range of trees, shrubs, fruit crops, and legumes. The adults usually feed on fruit and the immatures (nymphs) tend to feed on leaves and stems as well as fruit. Heavy feeding on fruit will cause the fruit surface to become depressed, spongy, and often discoloured.
Leaves that have been fed on usually develop stippled areas approximately 1/8 inch in diameter. In New Jersey, large numbers have been seen feeding on late-season peaches.
The brown marmorated stink bug is an indirect pest because it invades houses and other buildings in the fall. Large numbers of this stink bug will enter houses to spend the winter. Before entering the building they will congregate on the exterior walls. As the name, ‚Äústink bug,‚Äù suggests these insects are capable of emitting a strong, foul odour if disturbed.
The general body shape and appearance of the brown marmorated stink bug is similar to most other stink bugs. It is between ¬Ω and ¬æ inch long, shield-shaped, and dark brown in color. The wings do not quite cover the abdomen allowing the distinct, alternating black and white abdominal segments to show. The last two antennal segments have an alternating light and dark pattern. The margins of the pronotum are smooth.
If you suspect that you have found this insect, contact your local county Extension office.