As the Termites Chew

Entomologists Check the Effectiveness of Different Types of Pest Controls

by Suzanne Clark

Back in 1993 the Forest Products lab and the Forest Service constructed a tiny wood frame house at the lab in Richmond.

Christened "Villa Termiti," the building was designed to be eaten by termites while researchers applied and evaluated different pest control measures. For the last three years, the termites have been eating and the researchers observing.

They compared the effectiveness of heat, cold, electrocution, microwaves and two fumigants.

The result: a 90-page report submitted in April to the state's Structural Pest Control Board of the Department of Consumer Affairs.

The report offers information to help anyone with a drywood termite problem make a sound decision about control measures, says Vernard Lewis, cooperative extension specialist and report co-author.

The study was a test under "best case conditions." Under field conditions, the exact locations of termites may be unknown and treatments not done as carefully.

"Determining the extent of the drywood termite infestation is probably the most difficult part of the job," says Lewis.

Among highlights of the report:

* Test results reveal that only the fumigant gases demonstrated near 100 percent elimination of drywood termites. Whole-structure treatment with heat was very similar.

* For localized treatments, high doses of liquid nitrogen and lengthy applications of electricity using drill-and-pin techniques were at least 90 percent effective. Microwaves achieved 90 percent control, but only when treating naturally infested boards.

* Electrocution without the drill-and-pin technique and liquid nitrogen doses less than 8 pounds per cubic foot of wall void were not effective, even at the 90 percent control level.

* Six test boards were scorched during microwaving and minimal visible signs of damage to the test building were noted for whole-structure heating. Although damage may occur from fumigation, heat or microwaves, it is a certainty for liquid nitrogen (repairs to drilled holes in wall voids) and electrocution (damage during drilling and pinning).

The Structural Pest Control Board provided funding, as did Pest Control Operators of California and several state pest control firms.

This summer, a condensed report will appear in the Journal of Entomology, and a summary will be published in the UC Davis Pest Notes.

To order the $15 report, send a check payable to UC Regents with name, address and phone number to Report on Alternatives, c/o Vernard Lewis, 201 Wellman Hall, Berkeley, CA. 94720-3112.


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