Ask the Expert: Cockroaches, Clothes Moths, Wasps and Phorid Flies


March 26, 2015

Q. A technician found cockroaches in a commercial pantry and identified them as Asian cockroaches. I have my doubts. Can you verify this? They were found crawling up a wall in the pantry. Frank D., NEW YORK

A. Asian cockroaches look like German cockroaches, but they live outdoors primarily and don’t breed indoors. I doubt you have Asian cockroaches. You can send me a specimen, but to differentiate Asian from German cockroaches, you need a gas chromatograph study. I’m not equipped to do this. However, I was able to use the photos you sent me to identify the species as brown-banded cockroaches, which do wander on walls and ceilings. They breed indoors, but aren’t usually associated with food products. My guess is they were shipped in with product, and were wandering to find a better habitat.

Q. A homeowner’s wool carpet has been heavily damaged by clothes moths. She’s going to discard the carpet. A thorough search in the home failed to identify any other wool products. Is any treatment needed after the source is removed? Should I propose a crack-and-crevice treatment for the room in question? John B., NEW YORK

A. Clothes moth larvae tend to remain on the food source to pupate. Unlike Indianmeal moth larvae, which migrate to pupate, removing the source usually solves the problem. If the carpet is being removed, I don’t see the need for any treatment. Consider placing clothes moth monitors in the house. If any additional moths are captured, the new source must be located and treated or discarded.

Q. A homeowner has many mud dauber nests on her home. I plan to knock them down and clean off the mud. Do I need to do any treatment? Can I prevent this from happening in the future? George S., OKLAHOMA

A. During the winter, the mud cells contain mature larvae or pupae. Theres no need to treat, because the immature stages will die once exposed to the elements. Next season, you can sell the homeowner a preventive program that includes applying a residual to the areas likely to be colonized by the wasps. This would include under the eaves and under porches, because the wasps like protected areas to prevent rain from reaching the mud nests. One treatment should provide control for the season.

Q. I am finding phorid flies in a mobile home. They seem to be concentrated in the bathroom and kitchen. Ive had experience with these flies under slabs when waste lines leak, but this mobile home is several feet above ground. Where should I begin looking for a source? I can’t find one in the home itself. Fred H., FLORIDA

A. If you can’t locate a source, it must be on the exterior. Look for waste seepage in the soil beneath the mobile home. You might have a broken waste line and phorids breeding in the contaminated soil. Control is the same as when you find them under slabs: Locate the break, repair it and remove all contaminated soil. Also, check for openings around the waste lines as they exit the mobile home.

Email your questions about insect identification and pest management technologies and techniques to Dr. Mampe, an industry consultant, at Your questions most likely will be printed and answered in one of Pest Management Professional’s upcoming Ask the Expert columns.

Leave A Comment

Comments are closed.