American Cockroaches: Some Situations Continue Forever


August 18, 2014

We preach that complete pest elimination is our goal and that we must seek the source to achieve this. I often tell pest management professionals (PMPs) to start with four questions:

1. What is it?
2. Why is it here?
3. How do you eliminate it as soon as possible?
4. What do you need to do to prevent it from reoccurring?

There are some situations in which the first two questions are easy to answer, but it’s almost impossible to resolve the other questions.

I have fought ongoing American cockroach (Periplaneta americana) populations in large apartment and office buildings, as well as hotels and pharmaceutical plants. Occasionally, the cockroaches were there at least 50 years before I arrived — and just might remain there for as long as the structure stands. Real-life illustrations of this are:

Sewage smorgasbord
Picture a large hospital, more than 50 years old. Almost every night for more than a year, about 25 to 50 American cockroaches are observed on the ground-floor kitchen. During the day, none are seen. Normal PMP procedures of weekly service aren’t working.

An inspection reveals a huge crawlspace expanding throughout the majority of the building. By dropping through a trap door in the basement directly between the kitchen, one gains access to the area needing treatment. What’s there makes you realize this is far beyond expectations: At least 100,000 American cockroaches are visible on pillars and the floor’s surface. The floor is not visible because it’s covered with more than a foot of raw sewage! As you touch the sewage and lift some of the crust, thousands of different-sized nymphs scatter. You can’t discern where the break in the sewer line is.

Using a baiting technique, you gain control over thousands of cockroaches, but it doesn’t even put a noticeable dent in the nymphs harboring in the crusted sewage. In fact, you discover dead rats that have been chewed on by the cockroaches.

Leading to even more frustration, you realize that after you’ve reported the situation to the appropriate hospital personnel, no corrective action is taken. It’s cheaper and less complicated to just continue to treat the area.

Unwanted guests
A luxurious hotel had an American cockroach problem with no solution in sight. The pest management staff maintains the cockroaches are coming from the sewer and are established in the pipes in wall voids. They are correct, but can’t rip open the walls and remove the unused pipes or cap piping where needed.

I suggest capturing escaping cockroaches, including baiting on glueboards and using a fan to draw the cockroaches to the boards. Power treating sewer lines and other pipe areas with Drione will slow down the cockroaches, but not eliminate them. With the use of steam and/or colored smoke, the pest management staff will be able to locate holes in existing pipes better and repair them. As the building continues to age, new cracks in pipes will occur. Realistically, the problem will continue.

■ Know the history of your account and its physical location.
■ Don’t promise the customer more than you can deliver. Be honest about what you can and can’t do and why.
■ Develop strong communication bonds with your clients.
■ Know ahead of time when construction will occur, particularly at the lower levels, and what plumbing work might be done.
■ Go beyond catchbasins, sewers and drainage areas.
■ Cap all open pipes.
■ Request toilets don’t go dry.

Sad but true, sometimes complete pest elimination isn’t realistic. Sometimes a stalemate is the best a PMP can deliver.

You can reach Dr. Frishman, an industry consultant since 1967 and president of AMF Pest Management Services, at

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