Dealing with the notorious stink bug

October 21, 2008

Public enemy No. 1 in Washington County is the brown, marmorated stink bug. This pesky pest is clustering on our homes and sneaking inside to the frustration of most local residents. As our local Extension "bug and plant lady," I would like to share some facts on their background and control.

First of all, these bugs don't belong here. They came here from Asia, leaving their natural predators and controls behind. That's why there are so many around. Nothing eats them. They apparently taste as bad as they smell.

As bad as they smell, stink bugs aren't harmful. They don't bite. They don't sting. They feed on plants only. Their smell and their numbers are what offend us.

Why are they mobbing our homes? They come from a warmer climate and can't handle our cold winters. To stay alive, they tuck into tiny cracks in siding, wall voids, attics and any other small space that is warm. They spend their winters tucked away in semi-hibernation, not feeding, breeding or doing any harm.


With stink bugs, the best offense is a good defense. Seal up cracks they might sneak into. Grab your silicone caulk gun and seal around windows, doors, siding, baseboards, utility pipes, ceiling lights, exhaust fans and other openings. Repair or replace torn screens.

If they do enter your home, grab a bag or your vacuum. I pop any strays that get into my home into a sealed bag and toss it in the trash. You can also vacuum them up, emptying the bag if you get more than a few. The "stink" in "stink bug" is well deserved.

Chemicals don't control stink bugs. A few heavy-duty chemicals may kill a few, but thousands more are waiting in the wings to tuck into your home. So, chemicals don't fix the problem.

We don't recommend spraying insecticides inside or outside your home for stink bugs. Outside perimeter sprays of synthetic pyrethroids by certified pesticide applicators kill some stink bugs, but last only a few days because they break down in the sun. Since stink bugs try to get into your home for about six weeks, this doesn't control the problem.

Synthetic pyrethroids also have health risks for both humans and pets. We never recommend spraying insecticides in your home due to health concerns. Pesticides are poisonous.

Other academic sources agree that chemicals do not control stink bugs. Ohio State University reports, "Insecticides will not stop additional invasions and exposure of humans and pets to pesticides should be avoided."

According to the Penn State entomology department, "Although aerosol-type pyrethrum foggers will kill stink bugs on ceilings and walls, it will not prevent more of the insects from emerging after the room is aerated. Spray insecticides directed into cracks and crevices will not prevent more bugs from emerging."

Rutgers University adds, "To control stink bugs, the best method is to prevent them from entering your home. Control (with pesticides) may be difficult to achieve."

The bottom line is that stink bugs are a nuisance but not harmful. Chemicals don't solve the problem. Sealing up your home helps a great deal. And in a few weeks when the temperatures dip past freezing, they will be tucked away for the winter, a distant - albeit frustrating - memory.

Annette Ipsan is the Extension educator for horticulture and the Master Gardener program in Washington County for the University of Maryland Cooperative Extension. She can be reached weekdays by telephone at 301-791-1604, or by e-mail at

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