Dr. Vernard Lewis, long-time cooperative extension specialist for the University of California-Berkeley and his research team are working hard to help termite inspectors do a better job. They aid them by identifying drywood termite detection tools that are affordable and effective.
“The industry needs portable termite detection equipment to determine active from inactive infestations and to pinpoint exactly where an active infestation is. Non-destructive tools are the most important as they reduce damage and cost and leave no evidence of their usage,” he said.
“When it comes to structural pests, termites by far are the No. 1 destructive insects in the U.S.A., even though bed bugs are prominently in the news these days. In California, Florida and Hawaii, drywood termites, probably in that order, cause great amounts of damage with significant economic impact. Costs for control and repair of damage from drywood termites in California, for instance, exceed $300 million annually. So you can readily see the need for the best technologies and products to detect and treat for them.”
He discussed his research on that topic in Boston at NPMA PestWorld 2012. “We do lab and field studies designed to evaluate and improve inspections and treatments for inaccessible drywood termite infestations,” he explained.
“The problem with termite control is how do you really know you have an infestation,” he said. “Identifying the existence and limits of inaccessible drywood termite infestations is a great challenge. Inspection based on visual evidence alone can be inconclusive, especially infestations hidden from view.”
Lewis listed a number of detection devices and methods that his team and a California pest control company have studied as alternatives to visual searches. They included a form of termite radar, optical borescopes, electronic odor detectors, microwaves, acoustic emission (AE) equipment, infrared cameras and X-ray equipment. “These vary in price, complexity and levels of successful detection,” he said. In addition to these past studies, the Lewis Lab recently reviewed the TermatracT3i, a detection device that combines radar, moisture detection and thermal readings.
Because there has been much interest in California about these devices, the California Structural Pest Control Board several years ago asked him to test them both in the lab and in the field. In the past donations from the Structural Pest Control Board and the industry made funds available that enabled him to build “Villa Termiti,” a 400-foot wooden structure designed and constructed to research termite detection and treatment technology. The villa has a crawlspace and attic and, through the years, has been infested with subterranean and drywood termites, ants, beetles and bed bugs. “It allows us to do simulated field tests on termite detection and control products. The basic premise is this: if the detection device or control product works in our villa, there’s a good chance it will work in a home. It’s a lot better than a test tube or Petri dish tests,” he said.
Termites produce vibrations in wood by feeding and moving around. “Although some of these vibrations can be heard by human ears, the technology of AE devices amplifies and records vibrations that can’t be heard otherwise,” he explained. “These devices, which are manufactured by several companies, cost several thousands of dollars. The largest ones have up to nine sensors. Available AE surface and subsurface probes have been successful in detecting drywoods. But excessive background noise has sometimes resulted in false positive results for active termites.” He also said these devices are cumbersome and often difficult to hold still, which is essential in order not to confuse that noise with the sounds of the termites.
Dr. Lewis said he was surprised that AE devices, which were first introduced in Japan in the 1980s, haven’t been utilized more in the United States.
X-rays, of course, can penetrate all materials and have been used nondestructively to view insects in hidden locations. “Older x-ray technology,” he said, “was cumbersome and expensive to use. However, today’s portable x-ray devices are more effective and convenient, but are in the high-end cost category.”
He had one unit custom built for his research, which cost about $25,000. It takes images on a special, reusable phosphorus paper, which enables his research team to scan digital images. The paper itself costs $700.
Another detection device, the fiber optical borescope, uses visible light passing through a hollow tube to view termites and damage hidden behind walls. It’s best used in small and inaccessible areas. “A small hole must be drilled into walls to allow viewing,” he said. “They do a good job — best when wood and wall voids contain no insulation.In addition, using them may be physically challenging for an inspector, who may have to get down on knees on the floor, crawl about and take a very close and long look through the device. The borescopes on the market today,” he said, “are in the $300 cost range.”
Lewis and a research team also tested microwave devices, which he called a “speed trap” for drywoods. “Police catch speeders using microwave radar guns. These microwave devices for termite detection give off low level microwave energy and termites moving in that field set off recognizable signals that tell us of their presence. In past studies, the lab has conducted research on the Termatrac but recently we’ve been investigating the performance of the Termatrac3i that combines radar, moisture meter and thermal. Results should be obtained later this year.”
According to Dr. Lewis, infrared thermal imaging cameras detect body heat which is internally generated or reflected. The technology had been used for military surveillance as far back as World War II. It is used today for non-military uses such as night viewing for hunting, finding water leaks in walls and roofs, and locating faulty electrical connections. And it has been used for termite detection for the last decade or so.
“Infrared is part of the electromagnetic spectrum. It’s invisible to the eye and has a penetrating heating effect. Infrared thermal imaging cameras are very good at detecting temperature changes, but termites are cold-blooded and their temperatures don’t differ much from the wood they are infesting. We’ve found that using a heat gun may help us by changing the air temperature inside the termite galleries, but wall coverings still pose a formidable obstacle when trying to detect drywood termites behind walls,” he stated.
“Thermal imaging cameras detect heat at the surface area and read only the first 1/1000 of an inch of the surface, which means there has to be a congregation of termites within a nest in the void so that the heat generated actually penetrates to the surface. Detecting termites in voids is a challenge. These devices are complicated, require up to a five-day training course to learn how to use them and are very expensive.
According to Dr. Lewis, the Termatrac 3i also features a remote thermal sensor with a laser guide built in. “It performs a similar role to a thermal imaging camera; but without the display of an image. This enables the operator to point and scan to identify sudden changes in building surface temperature which is a common sign of moisture leaks and possible wood decay. It is easy to use and takes only a few minutes to learn. Data readings are recorded and stored to specific locations within the building and reports produced. Hopefully, effectiveness studies will be completed on this exciting detection innovation in the coming months.”
‘Elusive Silver Bullet.’
Dr. Lewis says he believes there is no single “silver bullet” among the detection devices on the market. “It is essential,” he emphasized, “to have termite detection experience and get effective training in the use of these advanced termite detection tools.”
The author is a contributuing writer for PCT and can be contacted at firstname.lastname@example.org.