This month Dr. Robert Smith, Department of Entomology, University of Arizona, answers questions about pest control services in Arizona.

Question: What is a pretreatment?

Answer: A pretreatment consists of a chemical treatment (with an EPA registered termiticide) of soil to form a barrier against subterranean termites invading a structure. A termite pretreatment is an important part of any structure built in Arizona.

Question: How do chemical barriers work?

Answer: Chemical barriers work by repealing/killing termites that contact the treated soil.

Question: Does pretreatment protect against all kinds of pest termites?

Answer: No. Pretreatments do not protect structures against dry wood termites.

Question: What are the chemicals used for pretreatment?

Answer: There are several including a new penetrating boric acid spray.

Question: Do all EPA registered termiticides perform equally well in protecting Arizona structures?

Answer: Absolutely not! The measures of the quality of a termiticides are how effective it is in excluding termites, and how long it lasts. In Arizona chlorpyrifos performs well initially but loses its effectiveness rapidly. Permethrin, on the other hand, is very persistent in Arizona, lasting longer than 15 years.

Question: Do all termiticides have the same performance in all parts of the county?

Answer: No. Every region has its best and worst performers and they differ from locality to locality.

Question: Why does chlorpyrifos perform so poorly in Arizona?

Answer: It is not known for certain, but the poor showing probably has something to do with our very high temperatures and our dry, alkaline soils.

Question: Are termiticides harmful to people?

Answer: All pesticides are potentially injurious to humans, pets, and other non-target organisms. Observe all label instructions. EPA registered termiticides are presumed to be safe for use in accordance with label instruction.

Question: Are pretreatments always effective in excluding termites?

Answer: Property applied and well-designed pretreatments can be expected to exclude termites from structures for many years.

Question: What constitutes a properly applied and well-designed pretreatment in Arizona?

Answer: A first-rate pretreatment requires cooperation between the applicator and the building contractor. In selecting the best termiticide for Arizona, use a 1% active ingredient (A.I.) concentration and the application of the termiticide at the highest labeled rate.

Question: Why do pretreatments fail within months or a few years after construction?

Answer: Pretreatment failures result from poor coordination between applicator and building contractor and or poor pretreatment design which may involve selection of a termiticide that does not hold up well in Arizona, using low concentration of active ingredient (A.I.), incomplete coverage of the soil, or use of an inadequate volume of finished spray.

Question: Is someone at fault if a pretreatment fails to exclude termites?

Answer: Absolutely! If your new house has a leaky roof, isn't there someone at fault and responsible to fix it?

Question: Is there a pretreatment for drywood termites?

Answer: Yes, in a manner of speaking. Well maintained painted wood cannot be infested by drywood termites. Also, the treatment of unpainted wood of any kind with a borate product such as Tim-bor (R) or Boracare (R) will render the wood uninfestable by termites of any kind so long as the wood is kept dry after treatment.

Question: What is the treatment for a structure infested with subterranean termites?

Answer: Remedial treatment for subterranean termites employs the same chemical termiticide that are used for pretreatment, but the termiticide must be applied using techniques that require special equipment. Essentially, remedial treatment attempts to renew a broken chemical soil barrier. Some of the retro-treatment techniques are subslab injection, rodding, trenching, treating, and backfilling.

Question: What is the treatment for a structural infestation of drywood termites?

Answer: Usually drilling the infested wood and injecting it with a termiticide is a reliable and economical treatment for drywood termites.

Question: I have a drywood termite infestation and my pest control company says I need to have my house tented and fumigated. This procedure is very expensive, is it really necessary?

Answer: No! Tenting and fumigation for the drywood termites that occur in Arizona is almost never necessary nor is it especially effective. Spot treatment is the effective and economical treatment for our drywood termites.

Question: If tenting is not really necessary and not especially effective why do pest control companies recommend the procedure?

Answer: Profit and marketing, pure and simple. Tenting and fumigation is a spectacularly showy pest control procedure that gives the consumer the impression he is getting a lot for his money. Fumigation is in fact a low overhead, extremely high profit operation. That's why the pest control industry likes it.

Question: How does the pest control operator know where to spot treat for drywood termites?

Answer: Drywood termites always produce sculptured pellet frass which they dispose of from so called "kick holes" in the infested wood. The telltale accumulations of drywood termite frass will show the homeowner where drywood termites are working and where the wood must be drilled and injected with termiticide. No frass, no drywood termites!

Question: How do I find a reliable pest control company?

Answer: Ask your friends and neighbors. Also, you may call fee Arizona Structural Pest Control Board and ask for fee complaint record for any licensed pest control company in Arizona. Finally, get proposals and bids from several companies to do the needed work. Ask questions about the proposed procedures and fees. Compare!

We will conclude this four-part series on termites next month with a discussion of wood infestation reports disclosure and buying a home in Arizona.