Ask the Expert: Wasps, Beetles and Fruit Flies


December 5, 2013

Q: Large wasps are digging in bare soil in a playground, so we dusted the holes, but there were more wasps than ever the next day. What’s the correct name for them, and how can I treat without a problem for the children? F.D., N.Y.

A: You might have cicada killers (Sphecius speciosus). Each female digs a hole, provisions it with a cicada, katydid, large grasshopper, etc., and lays an egg. She then digs another hole and repeats the process. The wasps usually spend the night in shrubbery nearby; they don’t rest in the holes they dug. Dusting the holes does little to control them because they might never return to that hole.
The best control method is to power spray the exposed soil and wet it to at least a quarter-inch. Less water will leave the pesticide on the soil surface and it will burn off before you have control. However, I wouldn’t spray soil in which kids are going to play. Tell the client to wait until the nesting season for the wasps is over, or cover the exposed soil with a thick layer of mulch (real or artificial).

Q: A homeowner covered his porch ceiling with knotty pine paneling. There’s a roof leak, and powderpost frass is falling from the paneling joints. There are no exit holes. He’s going to open the roof and replace it. What can I do to control this problem? Do I need to treat the paneling? W.O., Ala.

A: You probably have an Anobiid infestation in the rafters above the paneling. These beetles need the moisture content in the wood to be 14 percent or higher. Fixing the roof eventually will solve the problem. To hasten control, spray any rafters you can reach with a borate while the roof is open. There’s no need to treat the paneling because borate wouldn’t penetrate its finish.

Q: I service a restaurant with a fruit fly problem. I’ve explained to the owners many times they need better sanitation, but they don’t do it; yet they complain about the flies every time I arrive for service. How would you handle this account? F.I., Texas

A: If you don’t do anything except continue to go along with them, eventually these owners will cancel and badmouth you for poor service, so you have three options:

  • walk away from the account;
  • send them a letter explaining you can’t do anything about the flies unless they improve the sanitation; or
  • locate the specific sanitation problem, solve it yourself and bill them for your work. To help locate the breeding source(s), use fruit fly traps — one on either side of the suspect area — and hone in on the exact location by moving the traps closer.

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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