ARS scientists found these brown marmorated stink bug adults beneath the bark of a dead standing tree. Trees like this one provide cool, tight, dry, and protected locations for the bugs to spend the winter.
ARS scientists found these brown marmorated stink bug adults beneath the bark of a dead standing tree. Trees like this one provide cool, tight, dry, and protected locations for the bugs to spend the winter.

In 2013, U.S. Department of Agriculture (USDA) scientists surveyed forests in Maryland and West Virginia and found that stink bugs prefer to overwinter in large, dry, dead trees having a circumference of more than 23 inches.

Agricultural Research Service (ARS) entomologist Tracy Leskey and her team at the Appalachian Fruit Research Station in Kearneysville, West Virginia, surveyed the forests and found that oak and locust trees seem to be the favorite stink bug overwintering sites. According to Leskey, the porous dead tissue and peeling bark make a great place for the bugs to crawl into and hide. She found stink bugs in 33 percent of the trees fitting those parameters.

ARS is USDA's principal intramural scientific research agency.

The 2013 survey team included two detector dogs. The dogs were first trained to recognize the odor of adult stink bugs. Then, in indoor trials, they were guided by their handlers to find bugs hidden in cardboard boxes. Next, the dogs were trained in the field, where bugs were hidden beneath pieces of bark attached to living trees. In both indoor and outdoor trials, the dogs accurately detected target insects with greater than 84 percent accuracy.

Finally, the dogs were taken to woodland areas along the Appalachian Trail in Maryland. In these real-world conditions, the detector dogs were able to find wild overwintering stink bugs.

As part of a project known as the "Great Stink Bug Count," citizen volunteers from the Mid-Atlantic, Midwest, and Pacific Northwest regions of the United States recorded daily counts of stink bugs, along with their locations on residences and the time of each tally.

Landscape type seemed to have the greatest influence on overall stink bug numbers arriving at specific homes, according to Leskey. Homes located in mixed agriculture and woodland sites had the greatest number of stink bugs. On average, these homeowners counted over 3,000 stink bugs. Suburban and urban dwellers counted fewer stink bugs.