UNIVERSITY PARK, Pa. -- They're big, they're distinctively aromatic, and they're coming to a home near you. Stink bugs are on the move across Pennsylvania and a bug expert in Penn State's College of Agricultural Sciences says we should get ready for an extended stay.
Halyomorpha halys, better known as the brown marmorated stink bug, has been making its presence felt in many sections of eastern Pennsylvania. While stink bugs are native to the state, this current variety is a newly introduced species native to China, Japan, Taiwan and Korea that's spreading in all directions with surprising speed. Steve Jacobs, senior extension associate in entomology, says the harmless bugs' population explosion follows a familiar pattern.
"Insect pests introduced into new habitat usually don't have parasites or predators to hold them in check," Jacobs said. "These new stink bugs are following a pattern similar to Asian lady beetles in the state because they seek overwintering sites in households in the fall and re-emerge in the spring, which makes them a nuisance to homeowners. While they produce an unpleasant odor when squashed, they do not pose a threat to humans or cause structural damage to houses."
First reported in Lehigh County in September 1998, these exotic stinkbugs are now officially reported in 26 Pennsylvania counties and are spreading rapidly in New Jersey, Virginia, New York and Ohio.
"They've been reported and confirmed in Harrisburg, Butler, State College and Pittsburgh," he said. "They're probably in most if not all counties in the state already, with more in the eastern part of the state, particularly in the southeast. They'll almost certainly spread into new areas and the areas they're already in will see an increase in numbers."
The most efficient control measures for stink bugs in houses is mechanical exclusion – managing spaces where they can enter the house. Cracks around windows, doors, siding, utility pipes, behind chimneys and underneath wood fascia and other openings should be sealed with silicone or silicone-latex caulk. Damaged screens on doors and windows should be repaired or replaced.
"Because they're fairly large bugs, any entry points would be substantial cracks," Jacobs said. "The big thing is getting the house as tight as possible. Both live and dead stink bugs can be removed from interior areas with the aid of a vacuum cleaner but may produce a noticeable odor in the vacuum. Sprays don't help much once the insects have gained access to the wall voids or attic areas inside. Applications of insecticides outside your home can help control infestations when sealing the exterior is extremely difficult, and they should be applied by a licensed pest control operator in the fall."
In its native Asian habitats, the brown marmorated stink bug is a significant agricultural pest, attacking a variety of fruit species, ornamental plants and sometimes soy. Jacobs said thus far, stink bugs in America haven't been much of a problem for farmers.
"At this point, we're not aware of any orchard with problems with them, and commercial growers in the state are not having problems," he said. "Professional growers are probably already taking care of stink bugs as they spray for something else, but homeowners could have problems. We don't know how important stink bugs can be if they become more established."
While no one can predict the future, Jacobs advises homeowners to prepare for a long-term relationship with stink bugs. "People with the Asian lady beetle in their homes have been seeing them year after year, and probably stink bugs will be the same --you'll see them over and over again, every year."
EDITORS: Contact Steve Jacobs at 814-863-3963, or by e-mail at sbj2@psu.edu