Question

I just moved into a new apartment and now I have cockroaches for the first time in my life. I thought they were big black beetles but my neighbor said they are oriental cockroaches. She’s had a problem with them, too. The manager had my apartment treated but I still see them occasionally. What else can I do?

Answer

I bet anything that you are in a ground floor apartment. Oriental cockroaches are not normally a problem in residences… unless you are on ground level or basement level. There are two reasons for this: the cockroaches live outside around the foundation, and they like the higher humidity found at ground level. Once inside, they are usually found on lower levels near leaky pipes, floor drains, dishwashers, washing machines, or sinks. Their love for humidity is why some people call them “waterbugs.”

The oriental cockroaches are probably not breeding in your apartment, they are just finding their way in from outside. That brings me to the first thing you can do to help your situation:

1. Check for openings around your doors and windows where cockroaches could enter

Make sure that your sliding patio door has a tight seal around the bottom and sides. Look at the foundation walls around the outside of your apartment for any openings where pipes, cables, or electrical lines enter. Cockroaches can follow those lines and enter walls if there is a poor seal around the line. You might need to have management caulk spaces where these utilities enter.

2. Ask management to have the foundation treated by a pest control company

Oriental cockroaches scavenge on garbage and decaying materials. They have a high moisture requirement and are found outside in damp areas under mulch, in piles of leaves, under stones, in wood piles, under splash blocks, or around dumpsters or garbage cans. It’s probably more important to treat around the outside of your apartment. If oriental cockroaches are eliminated outside around the foundation where they live, there may be no need to treat inside apartments. Make sure that the pest control company also treats outside around your patio door or other door into your apartment.

3. Change the conditions around the outside of your apartment

If there is a lot of mulch around the outside door of your apartment or if you are near the dumpster, you are more likely to have oriental cockroaches nearby. Maybe you can get management to remove, or reduce, the mulch around your apartment. Mulch that remains wet from frequent watering is more likely to be home to various pests, including cockroaches.

4. Decrease the humidity in your apartment

It’s possible that your ground floor apartment has a higher humidity level than it should. You can use a dehumidifier or fans to lower the relative humidity inside. Oriental cockroaches are less likely to move from a more humid outside environment into a drier indoor environment. Although it’s not common, if indoor humidity is high enough, oriental cockroaches can breed and survive indoors.

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