I remember treating an apartment for German cockroaches with my Uncle Leonard.
He picked up a phone in the kitchen and told me, “Always treat the phone.”
“Why is that?” I asked.
He put the phone down. “Because once I had a callback and I went through the whole kitchen trying to figure out what I missed. I sprayed into the phone and thirty or forty roaches came running out! Now I always treat the phone.”
Knowing where to find German cockroach harborages is key to controlling them, whether you go old school and use a liquid treatment or whether you are using modern baits. You must find these harborages and treat every one of them.
Here’s some of the rules German cockroaches use when looking for a harborage. The more of these exist in an area, the more likely it is to be used as a harborage.
The Three W’s
Not to be confused with The Big W from It’s a Mad, Mad, Mad, Mad World. This is an old mnemonic device to help figure out where German cockroaches harbor.
We’ve all seen cockroaches in wooden cabinets (nowadays more likely particle board), but don’t confine the idea of wood just to this. Anything made with wood will count. Paper bags? Check. Cardboard? Check. Books, phone books, and so forth? Check again.
It’s not quite right to say “water,” but it works for the mnemonic device. What they are really attracted to is damp areas. Does the refrigerator drip at the condenser? There you have a source of water. Older refrigerators even have a drip pan and cardboard on the back. That gives you two checks. Wooden cabinets hold moisture from a dripping sink. That gives you another two checks.
Cockroaches are attracted to warm areas. Thinking back to the old refrigerator above, it had cardboard on the back (wood), a dripping condenser motor (water), and of course, if it’s running, warmth. This is why refrigerators can be a key harborage area in a home.
Finding German cockroach harborages is a matter of learning what makes for a good harborage and applying it in control situations. By all means, they can infest areas that don’t have any of these features, but they are more likely to be food where you have the more ideal conditions for them.
The Three W’s are just some of the factors to look for when trying to find German cockroach harborages. In a future post, we’ll look at some other key factors.
If you are interested in learning more about German cockroaches and their control, check out my class, Cockroaches 101: German Cockroach Control.