A stinky brown army is marching across Kentucky this fall, accidentally entering your homes and offices and they look for protective overwintering sites. Brown marmorated stink bugs leave a stain and a very unpleasant odor when mashed. Once winter ends, the insects move on and resume their normal life cycle. But they can leave a path of plant damage in their wake. You take charge and reclaim your structures and fields from these invaders.

The best treatment is prevention. First, you need to learn to differentiate between the brown marmorated stink bug and other types of insect look-alikes. The brown marmorated stink bug has the characteristic shield-shaped stink bug body. Winged adults are approximately five-eights-inch long with a mottled brown-gray body. The fourth segment of each antenna has a white band. Edges of the abdominal segments that extend laterally from under the wings are alternatively banded with black and white. The underside of the body is white to light gray with gray or black markings, and the legs are brown with faint white bands.

The best way to manage the insects is to seal up structures so they never make it inside in the first place. Look around your homes and other buildings for cracks around windows, doors, siding, utility pipes, behind chimneys, underneath the wood fascia and other openings. Seal the cracks with a good quality silicone-latex caulk. You should also repair or replace damaged screens on windows and doors.

Exterior insecticides may offer some relief from infestations when sealing a structure is difficult or impossible. Products containing active ingredients deltamethrin, cyfluthrin, lambda-cyhalothrin, cypermethrin or permethrin are some options for you to consider. You need to apply these products in the fall as the bugs begin to congregate. Sunlight will break down these chemicals, so you’ll have to stay vigilant and be ready to reapply every few days or every week to make sure they are effective.

If the bugs make it inside your home or building, try to find where the insects are entering and seal those entrances up with caulk. You can remove live and dead insects with a vacuum cleaner, but understand that your vacuum may acquire a smell of stink bugs for a time. Entomologists at the University of Kentucky College of Agriculture, Food and Environment don’t recommend using insecticides after bugs enter a structure. Although insecticidal dust treatments most likely will kill stink bugs, you will have a possible problem with carpet beetles feeding on the dead stink bugs and then moving on to your woolens or stored dry goods.

Aerosol foggers will kill stink bugs that have amassed on ceilings and walls. More insects often appear after the room is aerated. So these are just not good long-term solutions once you already have a problem.

For more information about the brown marmorated stink bug, contact the Boyle County Extension office.

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Jerry Little, County Extension Agent for Agriculture/Natural Resources