Termite problems? Try lahar

More than a decade since Mt. Pinatubo erupted, lahar has become a source of income and employment for about 30,000 people and LGUs in the area. Pampanga towns and the province itself have generated millions in taxes from lahar as quarry material while enterprising locals have produced exquisite handicraft with lahar components as base materials. The Mt. Pinatubo area has also been transformed into a tourist destination after the lahar carved and molded a dramatic landscape from the mountain.

This year, another use for lahar has been discovered. Dr. Menandro N. Acda, a professor at the College of Forestry and Natural Resources and currently chairman of the college’s Department of Forest Pro-ducts and Paper Science, has applied for a patent for a technology using lahar as a cost-effective physical barrier to protect wooden structures from subterranean termites.

In 2004, on a visit to a furniture plant in Pampanga, Dr. Acda was astonished by the amount of lahar that had buried the town of Bacolor and clogged the Pampanga river. Knowing that lahar is a sandy aggregate, Dr. Acda realized that it could be put to better use as an alternative method of termite control. He assiduously pursued his brainchild and was awarded research grants from the Charles Lindbergh Foundation and the Ford Conservation and Environmental Grants to support laboratory and field studies on the use of lahar as a termite barrier. 

Of the kinds of termites grouped according to their feeding behavior, it is subterranean termites that are primarily responsible for damage to wood structures. In the Philippines alone, termites cause tens of millions of dollars worth of property damage every year.

The most common method of termite control is the injection of chemical termiticides into the soil. In addition to being costly, this method is hazardous because termiticides are carcinogenic and can pollute the water table. Another method, using termite baits, costs approximately twice as much as chemical termiticides. Both methods are target specific and are not effective for all of the four most destructive termite species in the Philippines. Until recently, a third method – the use of a physical barrier – has not been available in the Philippines because processing materials (e.g., glass, granite or basalt) into termite barriers is energy intensive, expensive, and harmful to the environment . It was Dr. Acda’s curiousity and desire to find a solution to a common problem that changed this.

After three years, Dr. Acda confirmed his initial impression through laboratory, field, and pilot studies: lahar is indeed an effective termite barrier. Through his research, he was able to establish the right particle size effective for preventing the destructive activities of all of the four most pernicious termite species in the Philippines. He also found that the natural sharp edges of a lahar particle cut and kill termites when they try to burrow through a layer of the material.

Using lahar as a physical barrier is environment friendly and can provide additional income opportunities for people in the lahar areas of Pampanga and Albay.

Dr. Acda estimates that a small house with a 60-square-meter floor area would require about 10-12 cubic meters of screened lahar particles for installation beneath floors and along foundation walls. If commercialized, the cost of lahar barrier treatment would compare favorably with the use of conventional soil poisoning methods and termite baits. And its advantages give lahar a competitive edge over conventional poisoning and baiting.