By: Sandy Feather ©2010
Penn State Extension
Our office has been getting a lot of calls about stink bugs and they have even made the evening news. I have also been seeing a lot of stink bugs as I scout for woody ornamental insect and disease problems on a weekly basis, so this column addresses stink bugs.
Not all stink bugs are “bad.” Many of the stink bugs I’ve been seeing are spined soldier bugs. These are good bugs that are important predators of caterpillars, sawfly larvae and beetle larvae. Unfortunately, they look very much like the brown marmorated stink bugs that invade our homes in late summer, looking for a cozy place to spend the winter. Both have the “shield shape” characteristic of true bugs in the order Hemiptera. Both are various shades of brown, with light and dark bands alternating on their antennae.
Both have alternating light and dark bands along the edges of their wings at the rear of their bodies. But spined soldier bugs also have alternating bands of light and dark on their legs and prominent spines on their “shoulders” (pronotum). They are slightly smaller than brown marmorated stink bugs.
The brown marmorated stink bug was accidentally introduced into eastern Pennsylvania in the late 1990’s and has been reported in 37 of Pennsylvania’s 67 counties to date, including Allegheny County. It is likely that they can be found in all of Pennsylvania even though not all counties have gone on record. Brown marmorated stink bugs are native to China, Japan, Korea and Taiwan where they are considered important pests of fruits, vegetables and soybeans.
Brown marmorated stink bug
Like Asian multicolored lady beetles and boxelder bugs, brown marmorated stink bugs like to hibernate in our houses for the winter. They do not eat fabric or furniture and are not known to bite people or pets. They do cause concern when large numbers of them congregate on the sunny sides of houses in the fall, looking for a way in. They repeat this behavior in reverse in the spring (or even a warm, sunny day in winter), congregating on interior walls, looking for a way out. They emit an unpleasant odor when crushed or disturbed (hence the name “stink bug”). Researchers believe there is one generation of brown marmorated stink bugs a year in Pennsylvania’s climate.
The best way to deal with all of these nuisance pests is to keep them out of your house as much as possible. Screen all openings and attic vents. Make sure your window screens do not have holes in them and that the weather-stripping on doors fits snugly. Caulk all cracks around window and door frames, openings where utility pipes and wires enter your house and any other opening to the outdoors.
You can reduce brown marmorated stink bug congregations outdoors with sprays of synthetic pyrethroids, including the active ingredients cyfluthrin, deltamethrin, lambda-cyhalothrin, sumithrin or tralomethrin. A licensed structural pest control operator should apply these products in the fall, just before insects begin to congregate. Since many pesticides are broken down by exposure to sunlight, the residual effect of such applications may not last more than a week.
Do not spray these products inside your home. They will not prevent insects from coming in through unsealed crevices. Also, even though these products may kill many insects in wall voids, their decaying bodies may attract carpet beetles that will damage wool fabrics, grain products of all kinds, pet food, and many other food items. Use a vacuum to remove brown marmorated stink bugs and change the bag or empty the canister frequently.