Peridomestic Cockroaches


I’ve had people tell me about cockroaches as big as birds. Like tales of “the one that got away,” sizes are often exaggerated. From these stories, I know that the cockroaches in question are peridomestic cockroaches – “peri” meaning around, and “domestic” meaning home. These cockroaches generally live outdoors but make their way inside when environmental conditions change – it becomes too hot, too cold, too wet, too dry… pretty much anything that doesn’t constitute as a perfect day. They can breed indoors if the conditions are right, but it needs to be incredibly damp, like a chronically flooded basement. Most of the time, they are entering the home through gaps around plumbing or underneath doors that have damaged door sweeps. The peridomestic species that we encounter are the American, smoky brown, and Oriental cockroach.

American cockroaches are reddish brown with a greasy shine. They are our largest pest cockroach. They can reach up to two inches in length but rarely do they exceed an inch and a half. These cockroaches can fly, and when I was younger I remember trying to swat at these at the top of a wall, only to be terrified when they launched, wings fluttering, into my face. I imagine that most people fear insects because of an unpleasant experience they had with a big cockroach in their youth. When I was in high school, I was replacing a toilet paper roll and happened to look down into the tube while it was still in my grasp. There was a dark, shifty shape within. It’s amazing what the human brain can process in a mere fraction of a second, because I knew what it was without ever seeing its entire form. I dropped the roll, like any normal person, and jumped back and nearly collided with the bathroom wall. Somehow, I still decided to pursue entomology as a career.

Smoky brown cockroaches are uniformly deep brown in color with wings that extend beyond the length of the body. They get to be about an inch long. I had a thriving population of smoky brown cockroaches when I first moved into my house in Alabama. I know because I often found them on the floor at night when I was walking around barefoot. They are known for taking refuge in tree holes but, in this case, there weren’t any. It was near to autumn when I purchased my house, and the home was vacant for several months. Leaves were everywhere in the yard and in piles on the mulch. After the laborious process of moving in, I eventually got around to cleaning up the yard and found shed skins, young nymphs, and egg cases underneath the leaf piles. Minimal yard cleanup along with the installation of new door sweeps and weather-stripping solved my smoky brown cockroach problem. I haven’t seen one on my property in over a year.

Oriental cockroaches are glossy black and around three-quarters of an inch to an inch in length. The males have short wings that expose the segmented abdomen, while the female appears wingless (she has vestigial wing pads). They are sometimes called waterbugs because of their affinity for moisture. They love damp conditions, more so than the American and smoky brown cockroach, and can be found in basements, crawlspaces, floor drains, under sinks, and around outdoor garbage cans. Their presence may indicate moisture issues like plumbing leaks.

Exclusion and sanitation are the backbone of every successful control program. You can minimize your indoor contact with these cockroaches by caulking cracks, sealing up gaps around pipes, installing new door sweeps and weather-stripping, and ensuring that your garage door creates an impervious seal with the ground. Outdoor sanitation involves raking up and disposing of fallen leaves, removing yard debris, and relocating wood piles away from your house. A perimeter treatment can expedite their decline and prevent them from reestablishing.