Ask the Expert: Birds, Biting Insects and Yellowjackets


December 17, 2014

Q. A homeowner has a bird mite problem, so I removed a bird’s nest from the gutter and treated the inside of the affected room with a labeled insecticide. Four days later, there were still active bird mites in the room, which has tongue-and-groove paneling on all the walls. What do I do next? The homeowner is anxious. T.S., Minn.

A. I suspect you have mites hiding in the tongue-and-groove paneling and/or the attic insulation above. Check the attic and treat suspect areas if you find mites. Give the insecticide more time to work in the room so all the mites have an opportunity to contact the treatment.

Q. We’re experiencing a so-called bite problem in a commercial building’s offices and conference room. We’ve placed many sticky monitors but haven’t found any mites or insects. All areas in question have carpeting. The customer is becoming intolerant because we can’t solve the problem. Should we just spray the areas and hope for the best? R.H., Ohio

A. So far, you have done the correct thing: monitoring without pesticides. You might well have an environmental problem unrelated to insects or mites. Don’t treat unless you can identify a biting insect or mite. In the mind of the customer, treating confirms there’s an insect or mite present. The treatment will fail to solve the problem so the customer will ask you to treat again. Eventually, the customer will dump you and find someone else to solve the problem.

Bring in an industrial hygienist to sample the air for contaminants. You also might have static electricity from the carpet. That can be treated with an antistatic compound. Be a professional — don’t treat until the cause is known. In the long run, the customer will thank you for getting to
the root of the problem.

Q. I’ve failed to control yellowjackets behind brick veneers. Our normal procedure is to dust behind the veneer through the yellowjackets’ entry/exit hole with a silica gel dust followed by an injection of pyrethrins. Yellowjackets have stopped using their normal entry point but still show up indoors in occupied areas. Why is that occurring, and why is my usually successful treatment not working? J.B., Colo.

A. There could be several reasons why your treatment is failing under these conditions. Most brick veneers on residential homes have weep holes near the base to drain moisture, which reduces the effectiveness of silica gels. The silica clumps, and the target insects don’t die as quickly because they’re not desiccated. You can prevent that by using a normal insecticidal dust that incorporates an active ingredient.

Another possibility is the colony might be located far enough a way from the opening that your dust isn’t reach them. Because the dust is repellent, they might have found another way out of the confines behind the veneer. Locate the center of the colony by listening through the indoor walls (a stethoscope helps) and drill the veneer from the outside to reach the center of the colony.

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

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