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Home >> Departments/Offices >> Cooperative Extension >> Pest of the Month >> September



A lot of folks get grossed out by these large black roaches that appear on porches and sometimes in houses this time of year. These are smoky brown cockroaches. No exterminator is necessary for these insects. 

These insects live in wall voids and in outdoor voids (treeholes, hollow walls, and any other such void). They typically don't live in humans living areas, so treatment to these areas is not usually needed.  When they get inside, it is just incidental.

They do not have nests. The female carries an egg case around until the eggs are ready to hatch. It is a flat brown hard rectangular thing. It is a little under a half inch long and a quarter inch wide. She will leave it under the garbage can, damp napkins, or somewhere she knows there is food. They hatch soon after she drops the case. Crush them when you see them.

The first step to controlling them is to fix any entrance holes. Check windows and doors. This cockroach can slip into the house through small cracks and crevices. Chemically, you can control them with a perimeter pyrethroid insecticide spray on the outside of the home and/or a bait with Combat bait gel inside. You must use the large sized bait stations for smoky browns. Concentrate them under the washer and refrigerator. There are also gel baits that can be used, which comes in a tube. You squeeze a little here and there in areas they are likely to be - attics, crawlspaces, treeholes, hollow walls, and other voids outdoors. When using gel baits, the application of many small bait spots is preferred to the application of a few large bait spots. It is suggested to put some in the corners of the porch and in corners in the kitchen, bathroom or wherever you see the bugs.